Device and method for estimating angle of reception signal

ABSTRACT

Provided are a device and a method for estimating an angle of arrival (AoA) and an angle of departure (AoD) in a communication system having 1-bit quantization.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to wireless communication.

Related Art

The 6G system is aimed at (i) very high data rates per device, (ii) avery large number of connected devices, (iii) global connectivity, (iv)very low latency, (v) lower energy consumption of battery-free IoTdevices, (vi) an ultra-reliable connection, (vii) connected intelligencewith machine learning capabilities, etc. The vision of 6G systems can befour aspects: intelligent connectivity, deep connectivity, holographicconnectivity and ubiquitous connectivity.

In a 6G system, a larger number of antennas are required, and powerconsumption burden of a terminal increases to use a high-performance ADCwhile using a plurality of antennas. Accordingly, application of an ADChaving a low number of bits is being discussed in a 6G system. In thiscase, accuracy of AoA and AoD estimation may be a problem as an ADChaving a low number of bits is used.

SUMMARY

A method and apparatus for estimating an angle of arrival (AoA) and anangle of departure (AoD) in a communication system having 1-bitquantization are proposed.

According to the present specification, it is possible to increase theaccuracy of AoA and AoD estimation of a signal while using an ADC havinga low number of bits. Thus, communication efficiency increases.

Effects obtained through specific examples of this specification are notlimited to the foregoing effects. For example, there may be a variety oftechnical effects that a person having ordinary skill in the related artcan understand or derive from this specification. Accordingly, specificeffects of the disclosure are not limited to those explicitly indicatedherein but may include various effects that may be understood or derivedfrom technical features of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wireless communication system to which the presentdisclosure may be applied.

FIG. 2 is a diagram showing a wireless protocol architecture for a userplane.

FIG. 3 is a diagram showing a wireless protocol architecture for acontrol plane.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

FIG. 5 illustrates a functional division between an NG-RAN and a 5GC.

FIG. 6 illustrates an example of a frame structure that may be appliedin NR.

FIG. 7 shows a slot structure.

FIG. 8 illustrates a CORESET.

FIG. 9 is a diagram illustrating a difference between a conventionalcontrol region and the CORESET in NR.

FIG. 10 illustrates an example of a frame structure for new radio accesstechnology.

FIG. 11 is an example of a self-contained slot structure.

FIG. 12 is an abstract diagram of a hybrid beamforming structure interms of the TXRU and the physical antenna.

FIG. 13 shows a synchronization signal and a PBCH (SS/PBCH) block.

FIG. 14 is for explaining a method for a terminal to acquire timinginformation.

FIG. 15 illustrates an example of a system information acquisitionprocess of a UE.

FIG. 16 illustrates a random access procedure.

FIG. 17 illustrates a power ramping counter.

FIG. 18 illustrates the concept of the threshold of an SS block in arelationship with an RACH resource.

FIG. 19 is a flowchart illustrating an example of performing an idlemode DRX operation.

FIG. 20 illustrates a DRX cycle.

FIG. 21 shows an example of a communication structure that can beprovided in a 6G system.

FIG. 22 shows an example of a perceptron structure.

FIG. 23 shows an example of a multi-perceptron structure.

FIG. 24 shows an example of a deep neural network.

FIG. 25 shows an example of a convolutional neural network.

FIG. 26 shows an example of a filter operation in a convolutional neuralnetwork.

FIG. 27 shows an example of a neural network structure in which a cyclicloop exists.

FIG. 28 shows an example of an electromagnetic spectrum.

FIG. 29 is a diagram showing an example of a THz communicationapplication.

FIG. 30 illustrates an example of an electronic element-based THzwireless communication transceiver.

FIG. 31 illustrates an example of a method of generating a THz signalbased on an optical element.

FIG. 32 shows an example of an optical element-based THz wirelesscommunication transceiver.

FIG. 33 illustrates the structure of a photonic source basedtransmitter.

FIG. 34 illustrates the structure of an optical modulator.

FIG. 35 shows an example of a receiving device having a 64*64 2D patchantenna and a 1-bit ADC.

FIG. 36 schematically illustrates an example of a signal transmitted tobaseband by a 1-bit ADC.

FIG. 37 shows an example of a Uniform Linear Array (ULA) of antennas.

FIG. 38 is an example of a basic block diagram for explaining adelta-sigma structure in the spatial domain.

FIG. 39 shows an example of shaping according to the basic blockdiagram.

FIG. 40 shows an example of an AoA estimation structure based on Option1.

FIG. 41 shows an example of an AoA estimation structure based on Option2.

FIG. 42 schematically illustrates an example of a method for increasingphase resolution.

FIG. 43 schematically illustrates another example of a method forincreasing phase resolution.

FIG. 44 is a flowchart of an example of a method for measuring an angleof a received signal of a first communication device according to someimplementations of the present disclosure.

FIG. 45 illustrates a communication system 1 applied to the disclosure.

FIG. 46 illustrates a wireless device that is applicable to thedisclosure.

FIG. 47 illustrates a signal processing circuit for a transmissionsignal.

FIG. 48 illustrates another example of a wireless device applied to thedisclosure. The wireless device may be configured in various formsdepending on usage/service.

FIG. 49 illustrates a hand-held device applied to the disclosure.

FIG. 50 illustrates a vehicle or an autonomous driving vehicle appliedto the disclosure.

FIG. 51 illustrates a vehicle applied to the disclosure.

FIG. 52 illustrates a XR device applied to the disclosure.

FIG. 53 illustrates a robot applied to the disclosure.

FIG. 54 illustrates an AI device applied to the disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

As used herein, “A or B” may mean “only A”, “only B”, or “both A and B”.That is, “A or B” may be interpreted as “A and/or B” herein. Forexample, “A, B or C” may mean “only A”, “only B”, “only C”, or “anycombination of A, B, and C”.

As used herein, a slash (/) or a comma (,) may mean “and/or”. Forexample, “A/B” may mean “A and/or B”. Therefore, “A/B” may include “onlyA”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, B,or C”.

As used herein, “at least one of A and B” may mean “only A”, “only B”,or “both A and B”. Further, as used herein, “at least one of A or B” or“at least one of A and/or B” may be interpreted equally as “at least oneof A and B”.

As used herein, “at least one of A, B, and C” may mean “only A”, “onlyB”, “only C”, or “any combination of A, B, and C”. Further, “at leastone of A, B, or C” or “at least one of A, B, and/or C” may mean “atleast one of A, B, and C”.

As used herein, parentheses may mean “for example”. For instance, theexpression “control information (PDCCH)” may mean that a PDCCH isproposed as an example of control information. That is, controlinformation is not limited to a PDCCH, but a PDCCH is proposed as anexample of control information. Further, the expression “controlinformation (i.e., a PDCCH)” may also mean that a PDCCH is proposed asan example of control information.

Technical features that are separately described in one drawing may beimplemented separately or may be implemented simultaneously.

FIG. 1 shows a wireless communication system to which the presentdisclosure may be applied. The wireless communication system may bereferred to as an Evolved-UMTS Terrestrial Radio Access Network(E-UTRAN) or a Long Term Evolution (LTE)/LTE-A system.

The E-UTRAN includes at least one base station (BS) 20 which provides acontrol plane and a user plane to a user equipment (UE) 10. The UE 10may be fixed or mobile, and may be referred to as another terminology,such as a mobile station (MS), a user terminal (UT), a subscriberstation (SS), a mobile terminal (MT), a wireless device, etc. The BS 20is generally a fixed station that communicates with the UE 10 and may bereferred to as another terminology, such as an evolved node-B (eNB), abase transceiver system (BTS), an access point, etc.

The BSs 20 are interconnected by means of an X2 interface. The BSs 20are also connected by means of an S1 interface to an evolved packet core(EPC) 30, more specifically, to a mobility management entity (MME)through S1-MME and to a serving gateway (S-GW) through S1-U.

The EPC 30 includes an MME, an S-GW, and a packet data network-gateway(P-GW). The MME has access information of the UE or capabilityinformation of the UE, and such information is generally used formobility management of the UE. The S-GW is a gateway having an E-UTRANas an end point. The P-GW is a gateway having a PDN as an end point.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. Among them, a physical (PHY) layer belonging to the first layerprovides an information transfer service by using a physical channel,and a radio resource control (RRC) layer belonging to the third layerserves to control a radio resource between the UE and the network. Forthis, the RRC layer exchanges an RRC message between the UE and the BS.

FIG. 2 is a diagram showing a wireless protocol architecture for a userplane. FIG. 3 is a diagram showing a wireless protocol architecture fora control plane. The user plane is a protocol stack for user datatransmission. The control plane is a protocol stack for control signaltransmission.

Referring to FIGS. 2 and 3 , a PHY layer provides an upper layer with aninformation transfer service through a physical channel. The PHY layeris connected to a medium access control (MAC) layer which is an upperlayer of the PHY layer through a transport channel. Data is transferredbetween the MAC layer and the PHY layer through the transport channel.The transport channel is classified according to how and with whatcharacteristics data is transferred through a radio interface.

Data is moved between different PHY layers, that is, the PHY layers of atransmitter and a receiver, through a physical channel. The physicalchannel may be modulated according to an Orthogonal Frequency DivisionMultiplexing (OFDM) scheme, and use the time and frequency as radioresources.

The functions of the MAC layer include mapping between a logical channeland a transport channel and multiplexing and demultiplexing to atransport block that is provided through a physical channel on thetransport channel of a MAC Service Data Unit (SDU) that belongs to alogical channel. The MAC layer provides service to a Radio Link Control(RLC) layer through the logical channel.

The functions of the RLC layer include the concatenation, segmentation,and reassembly of an RLC SDU. In order to guarantee various types ofQuality of Service (QoS) required by a Radio Bearer (RB), the RLC layerprovides three types of operation mode: Transparent Mode (TM),Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provideserror correction through an Automatic Repeat Request (ARQ).

The RRC layer is defined only on the control plane. The RRC layer isrelated to the configuration, reconfiguration, and release of radiobearers, and is responsible for control of logical channels, transportchannels, and PHY channels. An RB means a logical route that is providedby the first layer (PHY layer) and the second layers (MAC layer, the RLClayer, and the PDCP layer) in order to transfer data between UE and anetwork.

The function of a Packet Data Convergence Protocol (PDCP) layer on theuser plane includes the transfer of user data and header compression andciphering. The function of the PDCP layer on the user plane furtherincludes the transfer and encryption/integrity protection of controlplane data.

What an RB is configured means a process of defining the characteristicsof a wireless protocol layer and channels in order to provide specificservice and configuring each detailed parameter and operating method. AnRB can be divided into two types of a Signaling RB (SRB) and a Data RB(DRB). The SRB is used as a passage through which an RRC message istransmitted on the control plane, and the DRB is used as a passagethrough which user data is transmitted on the user plane.

If RRC connection is established between the RRC layer of UE and the RRClayer of an E-UTRAN, the UE is in the RRC connected state. If not, theUE is in the RRC idle state.

A downlink transport channel through which data is transmitted from anetwork to UE includes a broadcast channel (BCH) through which systeminformation is transmitted and a downlink shared channel (SCH) throughwhich user traffic or control messages are transmitted. Traffic or acontrol message for downlink multicast or broadcast service may betransmitted through the downlink SCH, or may be transmitted through anadditional downlink multicast channel (MCH). Meanwhile, an uplinktransport channel through which data is transmitted from UE to a networkincludes a random access channel (RACH) through which an initial controlmessage is transmitted and an uplink shared channel (SCH) through whichuser traffic or control messages are transmitted.

Logical channels that are placed over the transport channel and that aremapped to the transport channel include a broadcast control channel(BCCH), a paging control channel (PCCH), a common control channel(CCCH), a multicast control channel (MCCH), and a multicast trafficchannel (MTCH).

The physical channel includes several OFDM symbols in the time domainand several subcarriers in the frequency domain. One subframe includes aplurality of OFDM symbols in the time domain. An RB is a resourcesallocation unit, and includes a plurality of OFDM symbols and aplurality of subcarriers. Furthermore, each subframe may use specificsubcarriers of specific OFDM symbols (e.g., the first OFDM symbol) ofthe corresponding subframe for a physical downlink control channel(PDCCH), that is, an L1/L2 control channel. A Transmission Time Interval(TTI) is a unit time (e.g., slot, symbol) for subframe transmission.

Hereinafter, a new radio access technology (new RAT, NR) will bedescribed.

As more and more communication devices require more communicationcapacity, there is a need for improved mobile broadband communicationover existing radio access technology. Also, massive machine typecommunications (MTC), which provides various services by connecting manydevices and objects, is one of the major issues to be considered in thenext generation communication. In addition, communication system designconsidering reliability/latency sensitive service/UE is being discussed.The introduction of next generation radio access technology consideringenhanced mobile broadband communication (eMBB), massive MTC (mMTC),ultrareliable and low latency communication (URLLC) is discussed. Thisnew technology may be called new radio access technology (new RAT or NR)in the present disclosure for convenience.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

Specifically, FIG. 4 illustrates a system architecture based on a 5G newradio access technology (NR) system. An entity used in the 5G NR system(hereinafter, simply referred to as “NR”) may absorb some or allfunctions of entities introduced in FIG. 1 (e.g., eNB, MME, S-GW). Anentity used in the NR system may be identified with the name “NG” todistinguish it from LTE.

Referring to FIG. 4 , the wireless communication system includes one ormore UEs 11, a next-generation RAN (NG-RAN), and a 5th generation corenetwork (5GC). NG-RAN consists of at least one NG-RAN node. An NG-RANnode is an entity corresponding to the BS 20 shown in FIG. 1 . An NG-RANnode consists of at least one gNB 21 and/or at least one ng-eNB 22. ThegNB 21 provides termination of the NR user plane and control planeprotocols towards the UE 11. Ng-eNB 22 provides termination of E-UTRAuser plane and control plane protocols towards UE 11.

5GC includes access and mobility management function (AMF), user planefunction (UPF) and session management function (SMF). AMF hostsfunctions such as NAS security, idle state mobility handling, and more.AMF is an entity that includes the functions of a conventional MME. UPFhosts functions such as mobility anchoring and protocol data unit (PDU)processing. A UPF is an entity that includes the functions of aconventional S-GW. The SMF hosts functions such as UE IP addressallocation and PDU session control.

The gNB and ng-eNB are interconnected through the Xn interface. gNB andng-eNB are also connected to 5GC through NG interface. Morespecifically, it is connected to the AMF through the NG-C interface andto the UPF through the NG-U interface.

FIG. 5 illustrates a functional division between an NG-RAN and a 5GC.

The gNB may provide functions such as an inter-cell radio resourcemanagement (Inter Cell RRM), radio bearer management (RB control),connection mobility control, radio admission control, measurementconfiguration & provision, dynamic resource allocation, and the like.The AMF may provide functions such as NAS security, idle state mobilityhandling, and so on. The UPF may provide functions such as mobilityanchoring, PDU processing, and the like. The SMF may provide functionssuch as UE IP address assignment, PDU session control, and so on.

FIG. 6 illustrates an example of a frame structure that may be appliedin NR.

Referring to FIG. 6 , a frame may consist of 10 milliseconds (ms) andmay include 10 subframes of 1 ms.

Uplink and downlink transmissions in NR may be composed of frames. Aradio frame has a length of 10 ms and may be defined as two 5 mshalf-frames (Half-Frame, HF). A half-frame may be defined as five 1 mssubframes (Subframes, SFs). A subframe is divided into one or moreslots, and the number of slots in a subframe depends on SubcarrierSpacing (SCS). Each slot includes 12 or 14 OFDM(A) symbols according toa cyclic prefix (CP). When a normal CP is used, each slot includes 14symbols. When an extended CP is used, each slot includes 12 symbols.Here, the symbol may include an OFDM symbol (or CP-OFDM symbol) and anSC-FDMA symbol (or DFT-s-OFDM symbol).

One or a plurality of slots may be included in the subframe according tothe subcarrier spacing.

The following table 1 illustrates a subcarrier spacing configuration µ.

TABLE 1 µ Δf = 2^(µ)·15[kHz] Cyclic prefix 0 15 Normal 1 30 Normal 2 60Normal Extended 3 120 Normal 4 240 Normal

The following table 2 illustrates the number of slots in a frame(N^(frame,µ)slot), the number of slots in a subframe (N^(subframe,µ)_(slot)), the number of symbols in a slot (N^(slot) _(symb)), and thelike, according to subcarrier spacing configurations µ.

TABLE 2 µ N^(slot) _(symb) N^(frame, µ) _(slot) N^(subframeµ) _(slot) 014 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

Table 3 below illustrates that the number of symbols per slot, thenumber of slots per frame, and the number of slots per subframe varydepending on the SCS, in case of using an extended CP.

TABLE 3 SCS(15*2^µ) N^(slot) _(symb) N^(frame,u) _(slot) N^(subframe,u)_(slot) 60 KHz (µ=2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)may be differently configured between a plurality of cells integrated toone UE. Accordingly, an (absolute time) duration of a time resource(e.g., SF, slot or TTI) (for convenience, collectively referred to as atime unit (TU)) configured of the same number of symbols may bedifferently configured between the integrated cells.

FIG. 7 shows a slot structure.

Referring to FIG. 7 , a slot includes a plurality of symbols in the timedomain. For example, in the case of a normal CP, one slot includes 14symbols, but in the case of an extended CP, one slot may include 12symbols. Alternatively, in the case of a normal CP, one slot includes 7symbols, but in the case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in the frequency domain. Aresource block (RB) may be defined as a plurality of (eg, 12)consecutive subcarriers in the frequency domain. A bandwidth part (BWP)may be defined as a plurality of consecutive (P)RBs in the frequencydomain, and may correspond to one numerology (eg, SCS, CP length, etc.).A carrier may include up to N (eg, 5) BWPs. Data communication may beperformed through an activated BWP. Each element may be referred to as aresource element (RE) in the resource grid, and one complex symbol maybe mapped.

A physical downlink control channel (PDCCH) may include one or morecontrol channel elements (CCEs) as illustrated in the following table 4.

TABLE 4 Aggregation level Number of CCEs 1 1 2 2 4 4 8 8 16 16

That is, PDCCH may be transmitted through a resource configured with 1,2, 4, 8, or, 16 CCE(s). Here, the CCE is configured with 6 REGs(resource element groups), and one REG is configured with one resourceblock in a frequency domain and one OFDM (orthogonal frequency divisionmultiplexing) symbol in a time domain.

Meanwhile, in NR, a new unit called a control resource set (CORESET) maybe introduced. The UE may receive the PDCCH in CORESET.

FIG. 8 illustrates a CORESET.

Referring to FIG. 8 , the CORESET includes NCORESETRB resource blocks inthe frequency domain, and N^(CORESET) _(symb) ∈ {1, 2, 3} number ofsymbols in the time domain. NCORESETRB and N^(CORESET) _(symb) may beprovided by a base station via higher layer signaling. As illustrated inFIG. 8 , a plurality of CCEs (or REGs) may be included in the CORESET.

The UE may attempt to detect a PDCCH in units of 1, 2, 4, 8, or 16 CCEsin the CORESET. One or a plurality of CCEs in which PDCCH detection maybe attempted may be referred to as PDCCH candidates.

A plurality of CORESETs may be configured for the UE.

FIG. 9 is a diagram illustrating a difference between a conventionalcontrol region and the CORESET in NR.

Referring to FIG. 9 , a control region 300 in the conventional wirelesscommunication system (e.g., LTE/LTE-A) is configured over the entiresystem band used by a base station (BS). All the UEs, excluding some(e.g., eMTC/NB-IoT UE) supporting only a narrow band, must be able toreceive wireless signals of the entire system band of the BS in order toproperly receive/decode control information transmitted by the BS.

On the other hand, in NR, the aforementioned CORESET was introduced. TheCORESETs 301, 302, and 303 may be referred to as radio resources forcontrol information to be received by the terminal, and may use only apart of the system bandwidth instead of the entire system bandwidth. Thebase station can allocate a CORESET to each terminal, and can transmitcontrol information through the allocated CORESET. For example, in FIG.9 , the first CORESET 301 may be allocated to terminal 1, the secondCORESET 302 may be allocated to terminal 2, and the third CORESET 303may be allocated to terminal 3. AUE in NR can receive controlinformation of a base station even if it does not necessarily receivethe entire system band.

The CORESET may include a UE-specific CORESET for transmittingUE-specific control information and a common CORESET for transmittingcontrol information common to all UEs.

Meanwhile, NR may require high reliability according to applications. Insuch a situation, a target block error rate (BLER) for downlink controlinformation (DCI) transmitted through a downlink control channel (e.g.,physical downlink control channel (PDCCH)) may remarkably decreasecompared to those of conventional technologies. As an example of amethod for satisfying requirement that requires high reliability,content included in DCI can be reduced and/or the amount of resourcesused for DCI transmission can be increased. Here, resources can includeat least one of resources in the time domain, resources in the frequencydomain, resources in the code domain and resources in the spatialdomain.

Meanwhile, in NR, the following technologies/features can be applied.

Self-Contained Subframe Structure

FIG. 10 illustrates an example of a frame structure for new radio accesstechnology.

In NR, a structure in which a control channel and a data channel aretime-division-multiplexed within one TTI, as shown in FIG. 10 , can beconsidered as a frame structure in order to minimize latency.

In FIG. 10 , a shaded region represents a downlink control region and ablack region represents an uplink control region. The remaining regionmay be used for downlink (DL) data transmission or uplink (UL) datatransmission. This structure is characterized in that DL transmissionand UL transmission are sequentially performed within one subframe andthus DL data can be transmitted and UL ACK/NACK can be received withinthe subframe. Consequently, a time required from occurrence of a datatransmission error to data retransmission is reduced, thereby minimizinglatency in final data transmission.

In this data and control TDMed subframe structure, a time gap for a basestation and a UE to switch from a transmission mode to a reception modeor from the reception mode to the transmission mode may be required. Tothis end, some OFDM symbols at a time when DL switches to UL may be setto a guard period (GP) in the self-contained subframe structure.

FIG. 11 is an example of a self-contained slot structure.

Referring to FIG. 11 , one slot may have a self-contained structure inwhich a DL control channel, DL or UL data, and a UL control channel mayall be included. For example, the first N symbols in a slot may be usedfor transmitting a DL control channel (in what follows, DL controlregion), and the last M symbols in the slot may be used for transmittingan UL control channel (in what follows, UL control region). N and M areeach an integer of 0 or larger. A resource region located between the DLand UL control regions (in what follows, a data region) may be used fortransmission of DL data or UL data. As one example, one slot maycorrespond to one of the following configurations. Each period is listedin the time order.

-   1. DL only configuration-   2. UL only configuration-   3. Mixed UL-DL configuration

-   DL region + GP (Guard Period) + UL control region-   DL control region + GP + UL region

Here, the DL region may include (i) a DL data region and (ii) a DLcontrol region + a DL data region. The UL region may include (i) a ULdata region and (ii) a UL data region + a UL control region.

In the DL control region, a PDCCH may be transmitted, and in the DL dataregion, a PDSCH may be transmitted. In the UL control region, a PUCCHmay be transmitted, and in the UL data region, a PUSCH may betransmitted. In the PDCCH, Downlink Control Information (DCI), forexample, DL data scheduling information or UL data schedulinginformation may be transmitted. In the PUCCH, Uplink Control Information(UCI), for example, ACK/NACK (Positive Acknowledgement/NegativeAcknowledgement) information with respect to DL data, Channel StateInformation (CSI) information, or Scheduling Request (SR) may betransmitted. A GP provides a time gap during a process where a gNB and aUE transition from the transmission mode to the reception mode or aprocess where the gNB and UE transition from the reception mode to thetransmission mode. Part of symbols belonging to the occasion in whichthe mode is changed from DL to UL within a subframe may be configured asthe GP.

Analog Beamforming #1

Wavelengths are shortened in millimeter wave (mmW) and thus a largenumber of antenna elements can be installed in the same area. That is,the wavelength is 1 cm at 30 GHz and thus a total of 100 antennaelements can be installed in the form of a 2-dimensional array at aninterval of 0.5 lambda (wavelength) in a panel of 5×5 cm. Accordingly,it is possible to increase a beamforming (BF) gain using a large numberof antenna elements to increase coverage or improve throughput in mmW.

In this case, if a transceiver unit (TXRU) is provided to adjusttransmission power and phase per antenna element, independentbeamforming per frequency resource can be performed. However,installation of TXRUs for all of about 100 antenna elements decreaseseffectiveness in terms of cost. Accordingly, a method of mapping a largenumber of antenna elements to one TXRU and controlling a beam directionusing an analog phase shifter is considered. Such analog beamforming canform only one beam direction in all bands and thus cannot providefrequency selective beamforming.

Hybrid beamforming (BF) having a number B of TXRUs which is smaller thanQ antenna elements can be considered as an intermediate form of digitalBF and analog BF. In this case, the number of directions of beams whichcan be simultaneously transmitted are limited to B although it dependson a method of connecting the B TXRUs and the Q antenna elements.

Analog Beamforming #2

When a plurality of antennas is used in NR, hybrid beamforming which isa combination of digital beamforming and analog beamforming is emerging.Here, in analog beamforming (or RF beamforming) an RF end performsprecoding (or combining) and thus it is possible to achieve theperformance similar to digital beamforming while reducing the number ofRF chains and the number of D/A (or A/D) converters. For convenience,the hybrid beamforming structure may be represented by N TXRUs and Mphysical antennas. Then, the digital beamforming for the L data layersto be transmitted at the transmitting end may be represented by an N byL matrix, and the converted N digital signals are converted into analogsignals via TXRUs, and analog beamforming represented by an M by Nmatrix is applied.

FIG. 12 is an abstract diagram of a hybrid beamforming structure interms of the TXRU and the physical antenna.

In FIG. 12 , the number of digital beams is L, and the number of analogbeams is N. Furthermore, in the NR system, a base station is designed tochange analog beamforming in symbol units, and a direction in which moreefficient beamforming is supported for a terminal located in a specificarea is considered. Furthermore, when defining specific N TXRUs and M RFantennas as one antenna panel in FIG. 12 , in the NR system, a method ofintroducing a plurality of antenna panels to which mutually independenthybrid beamforming is applicable is being considered.

As described above, when the base station utilizes a plurality of analogbeams, since analog beams that are advantageous for signal reception maybe different for each terminal, at least for synchronization signals,system information, paging, etc., a beam sweeping operation is beingconsidered in which a plurality of analog beams to be applied by a basestation are changed for each symbol in a specific subframe so that allterminals can have a reception opportunity.

FIG. 13 shows a synchronization signal and a PBCH (SS/PBCH) block.

According to FIG. 13 , the SS/PBCH block consists of PSS and SSS, eachoccupying 1 symbol and 127 subcarriers, and PBCH spanning 3 OFDM symbolsand 240 subcarriers, but leaving an unused portion for SSS on one symbolin the middle. The periodicity of the SS/PBCH block may be set by thenetwork, and the time position at which the SS/PBCH block may betransmitted may be determined by subcarrier spacing.

For PBCH, polar coding may be used. A UE may assume a band-specificsubcarrier spacing for an SS/PBCH block unless the network configuresthe UE to assume a different subcarrier spacing.

PBCH symbols carry their own frequency-multiplexed DMRS. QPSK modulationmay be used for PBCH. 1008 unique physical layer cell IDs may be given.

For a half frame having SS/PBCH blocks, first symbol indices forcandidate SS/PBCH blocks are determined according to the subcarrierspacing of the SS/PBCH blocks described later.

-   Case A Subcarrier spacing 15 kHz: The first symbols of candidate    SS/PBCH blocks have an index of {2, 8} + 14*n. For carrier    frequencies below 3 GHz, n = 0, 1. For carrier frequencies above 3    GHz and below 6 GHz, n = 0, 1, 2, 3.-   Case B Subcarrier spacing 30 kHz: The first symbols of candidate    SS/PBCH blocks have an index of {4, 8, 16, 20} + 28*n. For carrier    frequencies below 3 GHz, n=0. For carrier frequencies above 3 GHz    and below 6 GHz, n = 0, 1.-   Case C Subcarrier spacing 30 kHz: The first symbols of candidate    SS/PBCH blocks have an index of {2, 8} + 14*n. For carrier    frequencies below 3 GHz, n = 0, 1. For carrier frequencies above 3    GHz and below 6 GHz, n = 0, 1, 2, 3.-   Case D Subcarrier spacing 120 kHz: The first symbols of candidate    SS/PBCH blocks have an index of {4, 8, 16, 20} + 28*n. For carrier    frequencies above 6 GHz, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13,    15, 16, 17, 18.-   Case E Subcarrier spacing 240 kHz: The first symbols of candidate    SS/PBCH blocks have an index of {8, 12, 16, 20, 32, 36, 40, 44} +    56*n. For carrier frequencies above 6 GHz, n = 0, 1, 2, 3, 5, 6, 7,    8.

Candidate SS/PBCH blocks in a half frame are indexed in ascending orderfrom 0 to L-1 on the time axis. The UE must determine 2 LSB bits for L =4 and 3 LSB bits for L > 4 of the SS/PBCH block index per half framefrom one-to-one mapping with the index of the DM-RS sequence transmittedin the PBCH. For L=64, the UE needs to determine 3 MSB bits of SS/PBCHblock index per half frame by PBCH payload bits.

By the upper layer parameter ‘SSB-transmitted-SIB1’, indexes of SS/PBCHblocks in which the UE cannot receive other signals or channels withinREs overlapping with REs corresponding to the SS/PBCH blocks may be set.In addition, by the upper layer parameter ‘SSB-transmitted’, within REsoverlapping SS/PBCH blocks and corresponding REs, indexes of SS/PBCHblocks per serving cell in which the UE cannot receive other signals orchannels may be set. Settings by ‘SSB-transmitted’ can take precedenceover settings by ‘SSB-transmitted-SIB1’. Periodicity of a half frame forreception of SS/PBCH blocks per serving cell may be configured by anupper layer parameter ‘SSB-periodicityServingCell’. If the terminal doesnot receive the periodicity of the half frame for reception of SS / PBCHblocks, the terminal must assume periodicity of half frames. The UE mayassume that the periodicity is the same for all SS/PBCH blocks withinthe serving cell.

FIG. 14 is for explaining a method for a terminal to acquire timinginformation.

First, the terminal can obtain 6-bit SFN information through the MIB(Master Information Block) received in the PBCH. In addition, SFN 4 bitscan be obtained in the PBCH transport block.

Second, the UE can obtain a 1-bit half frame indicator as part of thePBCH payload. Below 3 GHz, the half frame indicator may be implicitlysignaled as part of the PBCH DMRS for Lmax=4.

Finally, the UE can obtain the SS/PBCH block index by the DMRS sequenceand PBCH payload. That is, LSB 3 bits of the SS block index can beobtained by the DMRS sequence during a period of 5 ms. Additionally, MSB3 bits of timing information are explicitly carried within the PBCHpayload (for above 6 GHz).

In initial cell selection, the UE may assume that half frames withSS/PBCH blocks occur with a periodicity of 2 frames. When SS/PBCH blockis detected, if k_(SSB≤)23 for FR1 and k_(SSB≤)11 for FR2, the UEdetermines that a control resource set for the Type0-PDCCH common searchspace exists. If k_(SSB)>23 for FR1 and k_(SSB)>11 for FR2, the UEdetermines that the control resource set for the Type0-PDCCH commonsearch space does not exist.

For a serving cell without transmission of SS/PBCH blocks, the UEacquires time and frequency synchronization of the serving cell based onreception of SS/PBCH blocks on the primary cell or PSCell of the cellgroup for the serving cell.

Hereinafter, acquisition of system information will be described.

System information (SI) is divided into a master information block (MIB)and a plurality of system information blocks (SIBs) where:

-   the MIB is transmitted always on a BCH according to a period of 80    ms, is repeated within 80 ms, and includes parameters necessary to    obtain system information block type1 (SIB 1) from a cell;-   SIB1 is periodically and repeatedly transmitted on a DL-SCH. SIB1    includes information on availability and scheduling (e.g.,    periodicity or SI window size) of other SIBs. Further, SIB1    indicates whether the SIBs (i.e., the other SIBs) are periodically    broadcast or are provided by request. When the other SIBs are    provided by request, SIB1 includes information for a UE to request    SI;-   SIBs other than SIB1 are carried via system information (SI)    messages transmitted on the DL-SCH. Each SI message is transmitted    within a time-domain window (referred to as an SI window)    periodically occurring;-   For a PSCell and SCells, an RAN provides required SI by dedicated    signaling. Nevertheless, a UE needs to acquire an MIB of the PSCell    in order to obtain the SFN timing of a SCH (which may be different    from an MCG). When relevant SI for a SCell is changed, the RAN    releases and adds the related SCell. For the PSCell, SI can be    changed only by reconfiguration with synchronization (sync).

FIG. 15 illustrates an example of a system information acquisitionprocess of a UE.

Referring to FIG. 15 , the UE may receive an MIB from a network and maythen receive SIB1. Subsequently, the UE may transmit a systeminformation request to the network and may receive a system informationmessage from the network in response.

The UE may apply a system information acquisition procedure foracquiring access stratum (AS) and non-access stratum (NAS) information.

In RRC_IDLE and RRC_INACTIVE states, the UE needs to ensure validversions of (at least) the MIB, SIB1, and system information block typeX (according to relevant RAT support for mobility controlled by the UE).

In an RRC _CONNECTED state, the UE needs to ensure valid versions of theMIB, SIB1, and system information block type X (according to mobilitysupport for relevant RAT).

The UE needs to store relevant SI obtained from a currentlycamping/serving cell. The version of the SI obtained and stored by theUE is valid only for a certain period of time. The UE may use thisversion of the stored SI, for example, after cell reselection, afterreturn from out of coverage, or after indication of a system informationchange.

Hereinafter, random access will be described.

A UE’s random access procedure may be summarized in Table 5.

TABLE 5 Type of signal Operation/obtained information Step 1 UplinkPRACH preamble To obtain initial beam Random election of RA-preamble IDStep 2 Random access response on DL-SCH Timing alignment informationRA-preamble ID Initial uplink grant, temporary C-RNTI Step 3 Uplinktransmission on UL-SCH RRC connection request UE identifier Step 4Downlink C-RNTI on PDCCH for initial access contention resolution C-RNTIon PDCCH for RRC_CONNECTED UE

FIG. 16 illustrates a random access procedure.

Referring to FIG. 16 , first, a UE may transmit a PRACH preamble as Msg1 of the random access procedure via an uplink.

Two random access preamble sequences having different lengths aresupported. A long sequence having a length of 839 is applied to asubcarrier spacing of 1.25 kHz and 5 kHz, and a short sequence having alength of 139 is applied to a subcarrier spacing of 15 kHz, 30 kHz, 60kHz, and 120 kHz. The long sequence supports an unrestricted set andrestricted sets of type A and type B, while the short sequence maysupport only an unrestricted set.

A plurality of RACH preamble formats is defined by one or more RACH OFDMsymbols, different cyclic prefixes (CPs), and a guard time. A PRACHpreamble setting to be used is provided to the UE as system information.

When there is no response to Msg1, the UE may retransmit thepower-ramped PRACH preamble within a specified number of times. The UEcalculates PRACH transmission power for retransmission of the preamblebased on the most recent estimated path loss and a power rampingcounter. When the UE performs beam switching, the power ramping counterdoes not change.

FIG. 17 illustrates a power ramping counter.

A UE may perform power ramping for retransmission of a random accesspreamble based on a power ramping counter. Here, as described above,when the UE performs beam switching in PRACH retransmission, the powerramping counter does not change.

Referring to FIG. 17 , when the UE retransmits the random accesspreamble for the same beam, the UE increases the power ramping counterby 1, for example, the power ramping counter is increased from 1 to 2and from 3 to 4. However, when the beam is changed, the power rampingcounter does not change in PRACH retransmission.

FIG. 18 illustrates the concept of the threshold of an SS block in arelationship with an RACH resource.

A UE knows the relationship between SS blocks and RACH resources throughsystem information. The threshold of an SS block in a relationship withan RACH resource is based on RSRP and a network configuration.Transmission or retransmission of a RACH preamble is based on an SSblock satisfying the threshold. Therefore, in the example of FIG. 18 ,since SS block m exceeds the threshold of received power, the RACHpreamble is transmitted or retransmitted based on SS block m.

Subsequently, when the UE receives a random access response on a DL-SCH,the DL-SCH may provide timing alignment information, an RA-preamble ID,an initial uplink grant, and a temporary C-RNTI.

Based on the information, the UE may perform uplink transmission of Msg3of the random access procedure on a UL-SCH. Msg3 may include an RRCconnection request and a UE identifier.

In response, a network may transmit Msg4, which can be considered as acontention resolution message, via a downlink. Upon receiving thismessage, the UE can enter the RRC-connected state.

Bandwidth Part (BWP)

In the NR system, up to 400 megahertz (MHz) per component carrier (CC)may be supported. If a terminal operating in such a wideband CC alwaysoperates with RF for all CCs turned on, battery consumption of theterminal may increase. Or when considering multiple use cases (e.g.eMBB, URLLC, mMTC, etc.) operating within one broadband CC, differentnumerologies (e.g., sub-carrier spacing (SCS)) may be supported for eachfrequency band within a corresponding CC. Alternatively, the capabilityfor the maximum bandwidth may be different for each terminal.Considering this, the base station may instruct the terminal to operateonly in a part of the bandwidth rather than the entire bandwidth of thewideband CC, for convenience, the corresponding partial bandwidth isdefined as a bandwidth part (BWP). BWP may be composed of consecutiveresource blocks (RBs) on the frequency axis, it may correspond to onenumerology (e.g., subcarrier spacing, cyclic prefix (CP) length,slot/mini-slot duration, etc.).

Meanwhile, the base station may set multiple BWPs even within one CCconfigured for the terminal. For example, in a PDCCH monitoring slot, aBWP that occupies a relatively small frequency domain is set, the PDSCHindicated by the PDCCH may be scheduled on a larger BWP. Alternatively,when terminals are concentrated in a specific BWP, some terminals may beset to other BWPs for load balancing. Alternatively, in consideration offrequency domain inter-cell interference cancellation betweenneighboring cells, a part of the spectrum in the middle of the entirebandwidth may be excluded and both BWPs may be configured even withinthe same slot. That is, the base station may set at least one DL/UL BWPto a terminal associated with a wideband CC, at least one DL / UL BWPamong the DL / UL BWP (s) configured at a specific time point can beactivated (by L1 signaling or MAC CE or RRC signaling, etc.), switchingto another set DL / UL BWP may be indicated (by L1 signaling or MAC CEor RRC signaling, etc.), when the timer value expires on a timer basis,it may be switched to a predetermined DL/UL BWP. At this time, theactivated DL / UL BWP is defined as an active DL / UL BWP. However, insituations such as when the terminal is in the initial access process orbefore the RRC connection is set up, this may not receive settings forDL/UL BWP, in this situation, the DL/UL BWP assumed by the UE is definedas an initial active DL/UL BWP.

DRX(Discontinuous Reception)

Discontinuous Reception (DRX) means an operation mode in which a userequipment (UE) reduces battery consumption so that the terminal candiscontinuously receive a downlink channel. That is, a UE set to DRX canreduce power consumption by discontinuously receiving DL signals.

The DRX operation is performed within a DRX cycle representing a timeinterval at which an On Duration is periodically repeated. The DRX cycleincludes an on-period and a sleep duration (or DRX opportunity). Theon-period indicates a time interval during which the UE monitors thePDCCH to receive the PDCCH.

DRX can be performed in Radio Resource Control (RRC) _IDLE state (ormode), RRC _INACTIVE state (or mode) or RRC _CONNECTED state (or mode).In RRC _IDLE state and RRC_INACTIVE state, DRX can be used to receivepaging signals discontinuously.

-   RRC _IDLE state: A state in which a radio connection (RRC    connection) between the base station and the terminal is not    established.-   RRC _INACTIVE state: A radio connection (RRC connection) is    established between the base station and the terminal, but the radio    connection is inactive.-   RRC _CONNECTED state: A state in which a radio connection (RRC    connection) is established between the base station and the    terminal.

DRX can be basically divided into idle mode DRX, connected DRX (C-DRX),and extended DRX.

DRX applied in the IDLE state may be referred to as idle mode DRX, andDRX applied in the CONNECTED state may be referred to as connected modeDRX (C-DRX).

Extended/Enhanced DRX (eDRX) is a mechanism that can extend the cyclesof idle mode DRX and C-DRX. Extended/Enhanced DRX (eDRX) can be mainlyused for (massive) IoT applications. In idle mode DRX, whether to alloweDRX may be set based on system information (e.g., SIB1). SIB1 mayinclude eDRX-allowed parameters. The eDRX-allowed parameter is aparameter indicating whether idle mode extended DRX is allowed.

Idle Mode DRX

In idle mode, the UE can use DRX to reduce power consumption. One pagingoccasion (PO) is a subframe that can be transmitted through thePaging-Radio Network Temporary Identifier (P-RNTI) (addresses pagingmessages for NB-IoT) Physical Downlink Control Channel (PDCCH) or MTCPDCCH (MPDCCH) or Narrowband PDCCH (NPDCCH).

In the P-RNTI transmitted through MPDCCH, PO may indicate the startsubframe of MPDCCH repetition. In the case of P-RNTI transmitted overNPDCCH, if the subframe determined by the PO is not a valid NB-IoTdownlink subframe, the PO may indicate the start subframe of the NPDCCHrepetition. Therefore, the first effective NB-IoT downlink subframeafter PO is the starting subframe of NPDCCH repetition.

One paging frame (PF) is one radio frame that may include one ormultiple paging opportunities. When DRX is used, the UE only needs tomonitor one PO per DRX cycle. One paging narrow band (PNB) is one narrowband in which a terminal performs paging message reception. PF, PO, andPNB may be determined based on DRX parameters provided in systeminformation.

FIG. 19 is a flowchart illustrating an example of performing an idlemode DRX operation.

According to FIG. 19 , the terminal may receive idle mode DRXconfiguration information from the base station through higher layersignaling (e.g., system information) (S21).

The UE may determine a Paging Frame (PF) and a Paging Occasion (PO) tomonitor the PDCCH in the paging DRX cycle based on the idle mode DRXconfiguration information (S22). In this case, the DRX cycle may includean on-period and a sleep period (or DRX opportunity).

The UE may monitor the PDCCH in the PO of the determined PF (S23). Here,for example, the UE monitors only one subframe (PO) per paging DRXcycle. In addition, when the terminal receives the PDCCH scrambled bythe P-RNTI during the on-duration (i.e., when paging is detected), theterminal transitions to the connected mode and can transmit and receivedata with the base station.

Connected Mode DRX(C-DRX)

C-DRX means DRX applied in the RRC connection state. The DRX cycle ofC-DRX may consist of a short DRX cycle and/or a long DRX cycle. Here, ashort DRX cycle may correspond to an option.

When C-DRX is configured, the UE may perform PDCCH monitoring for theon-period. If the PDCCH is successfully detected during PDCCHmonitoring, the terminal may operate (or execute) an inactive timer andmaintain an awake state. Conversely, if the PDCCH is not successfullydetected during PDCCH monitoring, the UE may enter the sleep state afterthe on-interval ends.

When C-DRX is configured, PDCCH reception opportunities (e.g., slotshaving a PDCCH search space) may be configured non-contiguously based onC-DRX configuration. In contrast, if C-DRX is not configured, in thepresent disclosure, PDCCH reception opportunities (e.g., slots having aPDCCH search space) may be continuously configured.

Meanwhile, PDCCH monitoring may be limited to a time interval set as ameasurement gap regardless of C-DRX configuration.

FIG. 20 illustrates a DRX cycle.

Referring to FIG. 20 , the DRX cycle consists of ‘On Duration’ and‘Opportunity for DRX’. The DRX cycle defines the time interval at whichthe ‘on-interval’ is repeated periodically. ‘On-interval’ indicates atime interval monitored by the UE to receive the PDCCH. When DRX isconfigured, the UE performs PDCCH monitoring during ‘on-period’. Ifthere is a successfully detected PDCCH during PDCCH monitoring, theterminal operates an inactivity timer and maintains an awake state. Onthe other hand, if there is no PDCCH successfully detected during PDCCHmonitoring, the UE enters a sleep state after the ‘on-interval’ ends.Therefore, when DRX is configured, PDCCH monitoring/reception may beperformed discontinuously in the time domain in performing the procedureand/or method described/suggested above. For example, when DRX isconfigured, in the present disclosure, PDCCH reception opportunities(e.g., slots having a PDCCH search space) may be configureddiscontinuously according to DRX configuration. On the other hand, whenDRX is not configured, PDCCH monitoring/reception may be continuouslyperformed in the time domain in performing the procedure and/or methoddescribed/proposed above. For example, when DRX is not configured, inthe present disclosure, PDCCH reception opportunities (e.g., slotshaving a PDCCH search space) may be continuously configured. Meanwhile,PDCCH monitoring may be limited in a time interval set as a measurementgap regardless of whether DRX is configured.

Table 6 shows the process of a UE related to DRX (RRC _CONNECTED state).Referring to Table 6, DRX configuration information is received throughhigher layer (e.g., RRC) signaling, and DRX ON/OFF is controlled by theDRX command of the MAC layer. When DRX is configured, PDCCH monitoringmay be performed discontinuously in performing the procedures and/ormethods described/suggested in this disclosure.

TABLE 6 Type of signals UE procedure step 1 RRCsignaling(MAC-CellGroupConfig) - Receive DRX setting information step 2MAC CE((Long) DRX command MAC CE) - Receive DRX command step 3 - - PDCCHmonitoring during the on-duration of the DRX cycle

The MAC-CellGroupConfig may include configuration information requiredto set medium access control (MAC) parameters for a cell group.MAC-CellGroupConfig may also include DRX-related configurationinformation. For example, MAC-CellGroupConfig defines DRX and mayinclude information as follows.

-   Value of drx-OnDurationTimer: defines the length of the start    section of the DRX cycle-   Value of drx-InactivityTimer: Defines the length of the time period    in which the UE remains awake after a PDCCH opportunity in which a    PDCCH indicating initial UL or DL data is detected-   Value of drx-HARQ-RTT-TimerDL: Defines the length of the maximum    time interval after DL initial transmission is received until DL    retransmission is received.-   Value of drx-HARQ-RTT-TimerDL: Defines the length of the maximum    time interval after the grant for UL initial transmission is    received until the grant for UL retransmission is received.-   drx-LongCycleStartOffset: Defines the time length and starting point    of the DRX cycle-   drx-ShortCycle (optional): defines the time length of the short DRX    cycle

Here, if any one of drx-OnDurationTimer, drx-InactivityTimer,drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerDL is in operation, the UEmaintains an awake state and performs PDCCH monitoring at every PDCCHopportunity.

Hereinafter, a 5G system or a 6G system will be described.

The 6G system is aimed at (i) very high data rates per device, (ii) avery large number of connected devices, (iii) global connectivity, (iv)very low latency, (v) lower energy consumption of battery-free IoTdevices, (vi) an ultra-reliable connection, (vii) connected intelligencewith machine learning capabilities, etc. The vision of 6G systems can befour aspects: intelligent connectivity, deep connectivity, holographicconnectivity and ubiquitous connectivity, the 6G system can satisfy therequirements shown in Table 7 below. That is, Table 7 is a table showingan example of requirements for a 6G system.

TABLE 7 Per device peak data rate 1 Tbps E2E latency 1 ms Maximumspectral efficiency 100bps/Hz Mobility support Up to 1000 km/hrSatellite integration Fully AI Fully Autonomous vehicle Fully XR FullyHaptic Communication Fully

6G system can have Enhanced mobile broadband (eMBB), Ultra-reliable lowlatency communications (URLLC), massive machine-type communication(mMTC), AI integrated communication, Tactile internet, High throughput,High network capacity, High energy efficiency, Low backhaul and accessnetwork congestion, and Key factors such as enhanced data security.

FIG. 21 shows an example of a communication structure that can beprovided in a 6G system.

The 6G system will have 50 times higher simultaneous wirelesscommunication connectivity than a 5G wireless communication system.URLLC, which is the key feature of 5G, will become more importanttechnology by providing end-to-end latency less than 1 ms in 6Gcommunication. At this time, the 6G system may have much bettervolumetric spectrum efficiency unlike frequently used domain spectrumefficiency. The 6G system may provide advanced battery technology forenergy harvesting and very long battery life and thus mobile devices maynot need to be separately charged in the 6G system. In addition, in 6G,new network characteristics may be as follows.

-   Satellites integrated network: To provide a global mobile group, 6G    will be integrated with satellite. Integrating terrestrial waves,    satellites and public networks as one wireless communication system    may be very important for 6G.-   Connected intelligence: Unlike the wireless communication systems of    previous generations, 6G is innovative and wireless evolution may be    updated from “connected things” to “connected intelligence”. AI may    be applied in each step (or each signal processing procedure which    will be described below) of a communication procedure.-   Seamless integration of wireless information and energy transfer: A    6G wireless network may transfer power in order to charge the    batteries of devices such as smartphones and sensors. Therefore,    wireless information and energy transfer (WIET) will be integrated.-   Ubiquitous super 3-dimemtion connectivity: Access to networks and    core network functions of drones and very low earth orbit satellites    will establish super 3D connection in 6G ubiquitous.

In the new network characteristics of 6G, several general requirementsmay be as follows.

-   Small cell networks: The idea of a small cell network was introduced    in order to improve received signal quality as a result of    throughput, energy efficiency and spectrum efficiency improvement in    a cellular system. As a result, the small cell network is an    essential feature for 5G and beyond 5G (5GB) communication systems.    Accordingly, the 6G communication system also employs the    characteristics of the small cell network.-   Ultra-dense heterogeneous network: Ultra-dense heterogeneous    networks will be another important characteristic of the 6G    communication system. A multi-tier network composed of heterogeneous    networks improves overall QoS and reduce costs.-   High-capacity backhaul: Backhaul connection is characterized by a    high-capacity backhaul network in order to support high-capacity    traffic. A high-speed optical fiber and free space optical (FSO)    system may be a possible solution for this problem.-   Radar technology integrated with mobile technology: High-precision    localization (or location-based service) through communication is    one of the functions of the 6G wireless communication system.    Accordingly, the radar system will be integrated with the 6G    network.-   Softwarization and virtualization: Softwarization and virtualization    are two important functions which are the bases of a design process    in a 5GB network in order to ensure flexibility, reconfigurability    and programmability.

Hereinafter, artificial intelligence (AI) among the core implementationtechnologies of the 6G system will be described.

Technology which is most important in the 6G system and will be newlyintroduced is AI. AI was not involved in the 4G system. A 5G system willsupport partial or very limited AI. However, the 6G system will supportAI for full automation. Advance in machine learning will create a moreintelligent network for real-time communication in 6G. When AI isintroduced to communication, real-time data transmission may besimplified and improved. AI may determine a method of performingcomplicated target tasks using countless analysis. That is, AI mayincrease efficiency and reduce processing delay.

Time-consuming tasks such as handover, network selection or resourcescheduling may be immediately performed by using AI. AI may play animportant role even in M2M, machine-to-human and human-to-machinecommunication. In addition, AI may be rapid communication in a braincomputer interface (BCI). An AI based communication system may besupported by meta materials, intelligent structures, intelligentnetworks, intelligent devices, intelligent recognition radios,self-maintaining wireless networks and machine learning.

Recently, attempts have been made to integrate AI with a wirelesscommunication system in the application layer or the network layer, butdeep learning have been focused on the wireless resource management andallocation field. However, such studies are gradually developed to theMAC layer and the physical layer, and, particularly, attempts to combinedeep learning in the physical layer with wireless transmission areemerging. AI-based physical layer transmission means applying a signalprocessing and communication mechanism based on an AI driver rather thana traditional communication framework in a fundamental signal processingand communication mechanism. For example, channel coding and decodingbased on deep learning, signal estimation and detection based on deeplearning, multiple input multiple output (MIMO) mechanisms based on deeplearning, resource scheduling and allocation based on AI, etc. may beincluded.

Machine learning may be used for channel estimation and channel trackingand may be used for power allocation, interference cancellation, etc. inthe physical layer of DL. In addition, machine learning may be used forantenna selection, power control, symbol detection, etc. in the MIMOsystem.

However, application of a deep neutral network (DNN) for transmission inthe physical layer may have the following problems.

Deep learning-based AI algorithms require a lot of training data inorder to optimize training parameters. However, due to limitations inacquiring data in a specific channel environment as training data, a lotof training data is used offline. Static training for training data in aspecific channel environment may cause a contradiction between thediversity and dynamic characteristics of a radio channel.

In addition, currently, deep learning mainly targets real signals.However, the signals of the physical layer of wireless communication arecomplex signals. For matching of the characteristics of a wirelesscommunication signal, studies on a neural network for detecting acomplex domain signal are further required.

Hereinafter, machine learning will be described in greater detail.

Machine learning refers to a series of operations to train a machine inorder to create a machine which can perform tasks which cannot beperformed or are difficult to be performed by people. Machine learningrequires data and learning models. In machine learning, data learningmethods may be roughly divided into three methods, that is, supervisedlearning, unsupervised learning and reinforcement learning.

Neural network learning is to minimize output error. Neural networklearning refers to a process of repeatedly inputting training data to aneural network, calculating the error of the output and target of theneural network for the training data, backpropagating the error of theneural network from the output layer of the neural network to an inputlayer in order to reduce the error and updating the weight of each nodeof the neural network.

Supervised learning may use training data labeled with a correct answerand the unsupervised learning may use training data which is not labeledwith a correct answer. That is, for example, in case of supervisedlearning for data classification, training data may be labeled with acategory. The labeled training data may be input to the neural network,and the output (category) of the neural network may be compared with thelabel of the training data, thereby calculating the error. Thecalculated error is backpropagated from the neural network backward(that is, from the output layer to the input layer), and the connectionweight of each node of each layer of the neural network may be updatedaccording to backpropagation. Change in updated connection weight ofeach node may be determined according to the learning rate. Calculationof the neural network for input data and backpropagation of the errormay configure a learning cycle (epoch). The learning data is differentlyapplicable according to the number of repetitions of the learning cycleof the neural network. For example, in the early phase of learning ofthe neural network, a high learning rate may be used to increaseefficiency such that the neural network rapidly ensures a certain levelof performance and, in the late phase of learning, a low learning ratemay be used to increase accuracy.

The learning method may vary according to the feature of data. Forexample, for the purpose of accurately predicting data transmitted froma transmitter in a receiver in a communication system, learning may beperformed using supervised learning rather than unsupervised learning orreinforcement learning.

The learning model corresponds to the human brain and may be regarded asthe most basic linear model. However, a paradigm of machine learningusing a neural network structure having high complexity, such asartificial neural networks, as a learning model is referred to as deeplearning.

Neural network cores used as a learning method may roughly include adeep neural network (DNN) method, a convolutional deep neural network(CNN) method and a recurrent Boltzmman machine (RNN) method. Such alearning model is applicable.

An artificial neural network is an example of connecting severalperceptrons.

FIG. 22 shows an example of a perceptron structure.

Referring to FIG. 22 , if the input vector x=(x1,x2,...,xd) is input,each component is multiplied by the weight (W1,W2,...,Wd), after summingup all the results, applying the activation function σ(·), the entireprocess above is called a perceptron. The huge artificial neural networkstructure may extend the simplified perceptron structure shown in FIG.22 and apply input vectors to different multi-dimensional perceptrons.For convenience of description, an input value or an output value isreferred to as a node.

Meanwhile, the perceptron structure shown in FIG. 22 can be described asbeing composed of a total of three layers based on input values andoutput values. An artificial neural network in which H number of (d + 1)dimensional perceptrons exist between the 1st layer and the 2nd layerand K number of (H + 1) dimensional perceptrons between the 2nd layerand the 3rd layer can be expressed as shown in FIG. 23 .

FIG. 23 shows an example of a multi-perceptron structure.

The layer where the input vector is located is called the input layer,the layer where the final output value is located is called the outputlayer, and all the layers located between the input layer and the outputlayer are called hidden layers. In the example of FIG. 23 , three layersare disclosed, but when counting the number of layers of an actualartificial neural network, since the count excludes the input layer, itcan be regarded as a total of two layers. The artificial neural networkis composed of two-dimensionally connected perceptrons of basic blocks.

The above-described input layer, hidden layer, and output layer can bejointly applied to various artificial neural network structures such asCNN and RNN, which will be described later, as well as multi-layerperceptrons. As the number of hidden layers increases, the artificialneural network becomes deeper, and a machine learning paradigm that usesa sufficiently deep artificial neural network as a learning model iscalled deep learning. In addition, the artificial neural network usedfor deep learning is called a deep neural network (DNN).

FIG. 24 shows an example of a deep neural network.

The deep neural network shown in FIG. 24 is a multi-layer perceptronconsisting of 8 hidden layers + 8 output layers. The multilayerperceptron structure is expressed as a fully-connected neural network.In a fully-connected neural network, there is no connection relationshipbetween nodes located on the same layer, and there is a connectionrelationship only between nodes located on adjacent layers. DNN has afully connected neural network structure and is composed of acombination of multiple hidden layers and activation functions, so itcan be usefully applied to identify the correlation characteristicsbetween inputs and outputs. Here, the correlation characteristic maymean a joint probability of input and output.

On the other hand, depending on how a plurality of perceptrons areconnected to each other, various artificial neural network structuresdifferent from the aforementioned DNN can be formed.

FIG. 25 shows an example of a convolutional neural network.

In DNN, nodes located inside one layer are arranged in a one-dimensionalvertical direction. However, in FIG. 25 , it can be assumed that thenodes are two-dimensionally arranged with w nodes horizontally and hnodes vertically (convolutional neural network structure of FIG. 25 ).In this case, since a weight is added for each connection in theconnection process from one input node to the hidden layer, a total ofhXw weights must be considered. Since there are hXw nodes in the inputlayer, a total of h2w2 weights are required between two adjacent layers.

FIG. 26 shows an example of a filter operation in a convolutional neuralnetwork.

The convolutional neural network of FIG. 25 has a problem that thenumber of weights increases exponentially according to the number ofconnections, so instead of considering all mode connections betweenadjacent layers, assuming that a filter having a small size exists, asshown in FIG. 26 , a weighted sum and an activation function operationare performed on a portion where the filters overlap.

One filter has weights corresponding to the number of filters, andlearning of weights can be performed so that a specific feature on animage can be extracted as a factor and output. In FIG. 26 , a 3×3 sizefilter is applied to the 3×3 area at the top left of the input layer,and the weighted sum and activation function calculations are performedon the corresponding node, and the resulting output value is stored inz22.

The filter scans the input layer while moving horizontally andvertically at regular intervals, performs weighted sum and activationfunction calculations, and places the output value at the position ofthe current filter. This operation method is similar to the convolutionoperation for images in the field of computer vision, so the deep neuralnetwork of this structure is called a convolutional neural network(CNN), a hidden layer generated as a result of the convolution operationis called a convolutional layer. Also, a neural network having aplurality of convolutional layers is referred to as a deep convolutionalneural network (DCNN).

In the convolution layer, the number of weights may be reduced bycalculating a weighted sum by including only nodes located in a regioncovered by the filter in the node where the current filter is located.This allows one filter to be used to focus on features for a local area.Accordingly, CNN can be effectively applied to image data processing inwhich a physical distance in a 2D area is an important criterion.Meanwhile, in the CNN, a plurality of filters may be applied immediatelybefore the convolution layer, and a plurality of output results may begenerated through a convolution operation of each filter.

Meanwhile, there may be data whose sequence characteristics areimportant according to data attributes. Considering the lengthvariability and precedence relationship of these sequence data, inputone element on the data sequence at each time step, a structure in whichan output vector (hidden vector) of a hidden layer output at a specificpoint in time is input together with the next element in a sequence toan artificial neural network is called a recurrent neural networkstructure.

FIG. 27 shows an example of a neural network structure in which a cyclicloop exists.

Referring to FIG. 27 , a recurrent neural network (RNN) is a structurethat applies a weighted sum and an activation function in the process ofinputting an element (x1(t), x2(t),,..., xd(t)) of any gaze t on thedata sequence to the fully connected neural network, by enteringtogether the hidden vector (z1(t-1), z2(t-1),..., zH(t-1)) of theimmediately preceding time point t-1. The reason why the hidden vectoris transmitted to the next time point in this way is that information inthe input vector at previous time points is regarded as beingaccumulated in the hidden vector of the current time point.

Referring to FIG. 27 , the recurrent neural network operates in asequence of predetermined views with respect to an input data sequence.

The hidden vectors (z1(1),z2(1),...,zH(1)) when the input vectors(x1(t), x2(t),,..., xd(t)) at time point 1 are input to the recurrentneural network is input together with the input vector(x1(2),x2(2),...,xd(2)) of time point 2, the vector(z1(2),z2(2),...,zH(2)) of the hidden layer is determined through theweighted sum and activation function. This process is repeatedlyperformed until time point 2, point 3, „, point T.

Meanwhile, when a plurality of hidden layers are arranged in a recurrentneural network, it is referred to as a deep recurrent neural network(DRNN). Recurrent neural networks are designed to be usefully applied tosequence data (e.g., natural language processing).

As a neural network core used as a learning method, in addition to DNN,CNN, and RNN, various deep learning techniques such as RestrictedBoltzmann Machine (RBM), deep belief networks (DBN), and deep Q-Networkmay be included. It can be applied to fields such as computer vision,voice recognition, natural language processing, and voice/signalprocessing.

Hereinafter, Terahertz (THz) communication among core implementationtechnologies of the 6G system will be described.

A data rate may increase by increasing bandwidth. This may be performedby using sub-TH communication with wide bandwidth and applying advancedmassive MIMO technology. THz waves which are known as sub-millimeterradiation, generally indicates a frequency band between 0.1 THz and 10THz with a corresponding wavelength in a range of 0.03 mm to 3 mm. Aband range of 100 GHz to 300 GHz (sub THz band) is regarded as a mainpart of the THz band for cellular communication. When the sub-THz bandis added to the mmWave band, the 6G cellular communication capacityincreases. 300 GHz to 3 THz of the defined THz band is in a far infrared(IR) frequency band. A band of 300 GHz to 3 THz is a part of an opticalband but is at the border of the optical band and is just behind an RFband. Accordingly, the band of 300 GHz to 3 THz has similarity with RF.

FIG. 28 shows an example of an electromagnetic spectrum.

The main characteristics of THz communication include (i) bandwidthwidely available to support a very high data rate and (ii) high pathloss occurring at a high frequency (a high directional antenna isindispensable). A narrow beam width generated in the high directionalantenna reduces interference. The small wavelength of a THz signalallows a larger number of antenna elements to be integrated with adevice and BS operating in this band. Therefore, an advanced adaptivearrangement technology capable of overcoming a range limitation may beused.

THz wireless communication uses a THz wave having a frequency ofapproximately 0.1 to 10 THz (1 THz = 10¹² Hz), and may mean terahertz(THz) band wireless communication using a very high carrier frequency of100 GHz or more. The THz wave is located between radio frequency(RF)/millimeter (mm) and infrared bands, and (i) transmitsnon-metallic/non-polarizable materials better than visible/infrared raysand has a shorter wavelength than the RF/millimeter wave and thus highstraightness and is capable of beam convergence. In addition, the photonenergy of the THz wave is only a few meV and thus is harmless to thehuman body. A frequency band which will be used for THz wirelesscommunication may be a D-band (110 GHz to 170 GHz) or a H-band (220 GHzto 325 GHz) band with low propagation loss due to molecular absorptionin air. Standardization discussion on THz wireless communication isbeing discussed mainly in IEEE 802.15 THz working group (WG), inaddition to 3GPP, and standard documents issued by a task group (TG) ofIEEE 802.15 (e.g., TG3d, TG3e) specify and supplement the description ofthis disclosure. The THz wireless communication may be applied towireless cognition, sensing, imaging, wireless communication, and THznavigation.

FIG. 29 is a diagram showing an example of a THz communicationapplication.

As shown in FIG. 29 , a THz wireless communication scenario may beclassified into a macro network, a micro network, and a nanoscalenetwork. In the macro network, THz wireless communication may be appliedto vehicle-to-vehicle (V2V) connection and backhaul/fronthaulconnection. In the micro network, THz wireless communication may beapplied to near-field communication such as indoor small cells, fixedpoint-to-point or multipoint connection such as wireless connection in adata center or kiosk downloading.

Table 8 is a table showing an example of a technology that can be usedin a THz wave.

TABLE 8 Transceivers Device Available immature: UTC-PD, RTD and SBDModulation and coding Low order modulation techniques (OOK, QPSK), LDPC,Reed Soloman, Hamming, Polar, Turbo Antenna Omni and Directional, phasedarray with low number of antenna elements Bandwidth 69 GHz (or 23 GHz)at 300 GHz Channel models Partially Data rate 100 Gbps Outdoordeployment No Free space loss High Coverage Low Radio Measurements 300GHz indoor Device size Few micrometers

Meanwhile, THz wireless communication can be classified based on themethod for generating and receiving THz. The THz generation method canbe classified as an optical device or an electronic device basedtechnology.

FIG. 30 illustrates an example of an electronic element-based THzwireless communication transceiver.

the method of generating THz using an electronic device includes amethod using a semiconductor device such as a resonance tunneling diode(RTD), a method using a local oscillator and a multiplier, a monolithicmicrowave integrated circuit (MMIC) method using a compoundsemiconductor high electron mobility transistor (HEMT) based integratedcircuit, and a method using a Si-CMOS-based integrated circuit. In thecase of FIG. 30 , a multiplier (doubler, tripler, multiplier) is appliedto increase the frequency, and radiation is performed by an antennathrough a subharmonic mixer. Since the THz band forms a high frequency,a multiplier is essential. Here, the multiplier is a circuit having anoutput frequency which is N times an input frequency, and matches adesired harmonic frequency, and filters out all other frequencies. Inaddition, beamforming may be implemented by applying an array antenna orthe like to the antenna of FIG. 30 . In FIG. 30 , IF represents anintermediate frequency, a tripler and a multiplier represents amultiplier, PA represents a power amplifier, and LNA represents a lownoise amplifier, and PLL represents a phase-locked loop.

FIG. 31 illustrates an example of a method of generating a THz signalbased on an optical element. FIG. 32 shows an example of an opticalelement-based THz wireless communication transceiver.

The optical device-based THz wireless communication technology means amethod of generating and modulating a THz signal using an opticaldevice. The optical device-based THz signal generation technology refersto a technology that generates an ultrahigh-speed optical signal using alaser and an optical modulator, and converts it into a THz signal usingan ultrahigh-speed photodetector. This technology is easy to increasethe frequency compared to the technology using only the electronicdevice, can generate a high-power signal, and can obtain a flat responsecharacteristic in a wide frequency band. In order to generate the THzsignal based on the optical device, as shown in FIG. 31 , a laser diode,a broadband optical modulator, and an ultrahigh-speed photodetector arerequired. In the case of FIG. 31 , the light signals of two lasershaving different wavelengths are combined to generate a THz signalcorresponding to a wavelength difference between the lasers. In FIG. 31, an optical coupler refers to a semiconductor device that transmits anelectrical signal using light waves to provide coupling with electricalisolation between circuits or systems, and a uni-travelling carrierphoto-detector (UTC-PD) is one of photodetectors, which uses electronsas an active carrier and reduces the travel time of electrons by bandgapgrading. The UTC-PD is capable of photodetection at 150 GHz or more. InFIG. 32 , an erbium-doped fiber amplifier (EDFA) represents an opticalfiber amplifier to which erbium is added, a photo detector (PD)represents a semiconductor device capable of converting an opticalsignal into an electrical signal, and OSA represents an optical subassembly in which various optical communication functions (e.g.,photoelectric conversion, electrophotic conversion, etc.) aremodularized as one component, and DSO represents a digital storageoscilloscope.

The structure of the photoelectric converter (or photoelectricconverter) will be described with reference to FIGS. 33 and 34 . FIG. 33illustrates the structure of a photonic source based transmitter. FIG.34 illustrates the structure of an optical modulator.

generally, the optical source of the laser may change the phase of asignal by passing through the optical wave guide. At this time, data iscarried by changing electrical characteristics through microwave contactor the like. Thus, the optical modulator output is formed in the form ofa modulated waveform. A photoelectric modulator (O/E converter) maygenerate THz pulses according to optical rectification operation by anonlinear crystal, photoelectric conversion (O/E conversion) by aphotoconductive antenna, and emission from a bunch of relativisticelectrons. The terahertz pulse (THz pulse) generated in the above mannermay have a length of a unit from femto second to pico second. Thephotoelectric converter (O/E converter) performs down conversion usingnon-linearity of the device.

Given THz spectrum usage, multiple contiguous GHz bands are likely to beused as fixed or mobile service usage for the terahertz system.According to the outdoor scenario criteria, available bandwidth may beclassified based on oxygen attenuation 10 \^2 dB/km in the spectrum ofup to 1 THz. Accordingly, a framework in which the available bandwidthis composed of several band chunks may be considered. As an example ofthe framework, if the length of the terahertz pulse (THz pulse) for onecarrier (carrier) is set to 50 ps, the bandwidth (BW) is about 20 GHz.

Effective down conversion from the infrared band to the terahertz banddepends on how to utilize the nonlinearity of the O/E converter. Thatis, for down-conversion into a desired terahertz band (THz band), designof the photoelectric converter (O/E converter) having the most idealnon-linearity to move to the corresponding terahertz band (THz band) isrequired. If a photoelectric converter (O/E converter) which is notsuitable for a target frequency band is used, there is a highpossibility that an error occurs with respect to the amplitude and phaseof the corresponding pulse.

In a single carrier system, a terahertz transmission/reception systemmay be implemented using one photoelectric converter. In a multi-carriersystem, as many photoelectric converters as the number of carriers maybe required, which may vary depending on the channel environment.Particularly, in the case of a multi-carrier system using multiplebroadbands according to the plan related to the above-described spectrumusage, the phenomenon will be prominent. In this regard, a framestructure for the multi-carrier system can be considered. Thedown-frequency-converted signal based on the photoelectric converter maybe transmitted in a specific resource region (e.g., a specific frame).The frequency domain of the specific resource region may include aplurality of chunks. Each chunk may be composed of at least onecomponent carrier (CC).

Meanwhile, the development direction of wireless communicationtechnology has been focused on increasing data transmission rate byutilizing wide bandwidth (BW) and multiple input multiple output (MIMO)technology. It is expected that higher frequencies will be used tosecure a wider bandwidth in future next-generation wirelesscommunications. For example, Beyond 5G or 6G worldwide is researchingcommunication transmission and reception technology in the highfrequency band from 0.1 THz to 10 THz. In addition, as the carrierfrequency increases, the free space path loss (FSPL) value physicallyincreases. Therefore, in order to overcome this, the transceiver mustderive a gain through beamforming technology by mounting a large numberof transmit/receive antennas.

As described above, in a next-generation wireless communication system,a transceiver supporting a wide bandwidth and supporting a large numberof antennas is required. However, in this case, in order to support ahigh data rate, the front-end of the transceiver must also support thecorresponding data rate. In particular, at the receiving end, ananalog-to-digital converter (ADC) also requires a high resolution and ahigh sampling rate.

It is obvious that an ADC supporting a high resolution and a highsampling rate accompanies a lot of power consumption. For example,current high-performance ADCs consume several Watts of power. Inaddition, in order to utilize multiple antennas, an RF chain is requiredfor each antenna and a plurality of ADCs are required. In this case,tens to hundreds of watts of power will be required.

The power requirement means a much larger amount of power than thebattery capacity currently used in the wireless device, especially fromthe point of view of reception, if power consumption of other hardwareincluding ADC is added, it may act as a bottleneck intransmission/reception technology.

In order to solve the above problem, two solutions considering energyefficiency can be considered. The first is to construct an RF chain thatincludes a much smaller number of high-performance ADCs than the numberof actual physical antennas, a hybrid beamforming method combininganalog beamforming and digital beamforming by connecting multipleantennas to each single RF chain may be considered. The method has theadvantage of reducing power consumption by using fewer ADCs than thenumber of physical antennas. On the other hand, analog beamforming has alow degree of freedom in beamforming, and a procedure for matchingreception analog beamforming causes overhead.

The second is to connect low-power RF chains to all physical antennas.In particular, in the case of an ADC, power consumption can be reducedexponentially by configuring a 1-bit comparator. In addition, there isan advantage of operating without automatic gain control (AGC). On theother hand, loss in terms of received signal information due to 1-bitquantization occurs, and linear system modeling in terms of transmit andreceive signals no longer fits, and thus a new transmission andreception technique is required.

Here, it is obvious that a new technique for estimating the existing AoAand AoD is required due to the information loss.

To this end, a receiving device having a 1-bit ADC for energy-efficientreception may be considered. At this time, information loss may occur asthe signal sent by the transmitter passes through the 1-bit ADC.

FIG. 35 shows an example of a receiving device having a 64*64 2D patchantenna and a 1-bit ADC.

Specifically, FIG. 35 shows an example of a receiving device of having4096 (64*64) antennas and the receiving path connected to each antennahaving an I (in-phase) signal, that is, a real signal, and a Q(Quadrature) signal, that is, an imaginary signal, each having a 1-bitADC. The RF front-end in front of the ADC is omitted.

FIG. 36 schematically illustrates an example of a signal transmitted tobaseband by a 1-bit ADC.

Here, in the conventional high-performance ADC, the received signal inthe form of a + bj (a and b are numbers represented by 8 to 10 bits,respectively) is transmitted to the baseband, the types of signalstransmitted to baseband by a 1-bit ADC are limited to four per receivepath. That is, it is limited to 1+j, 1-j, -1+j, and -1+j.

Therefore, in the case of AoA and AoD, which were estimated throughconventional phase estimation, such as phase estimation in the frequencydomain, performance degradation inevitably occurs. This leads todeterioration of performance of localization and beam search. Therefore,a new technique is needed to enhance the performance of AoA and AoD in1-bit ADC systems.

In the following, the proposal of the present disclosure will bedescribed in more detail.

The following drawings are made to explain a specific example of thepresent specification. Since the names of specific devices or names ofspecific signals/messages/fields described in the drawings are providedas examples, the technical features of the present specification are notlimited to the specific names used in the drawings below.

FIG. 37 shows an example of a Uniform Linear Array (ULA) of antennas.

Referring to FIG. 37 , in general, the physical distance betweenantennas can be divided as follows based on half of a wavelength of atransmission frequency. That is, if the distance between the antennas isless than ½ of the wavelength, it is called densely spaced or denselyspaced. This is called spatially oversampling. In addition, the case of½ is referred to as critically spaced or critically spaced, and isreferred to as Nyquist sampling. A case greater than ½ is called sparseplacement or sparsely spaced and is termed spatially undersampled.

In this specification, the physical distance between the antennas ismade smaller than half the length of the wavelength of the transmissionfrequency, a new method of estimating AoA and AoD based on oversamplingin the spatial domain and a method of enhancing performance through abaseband algorithm with a distance between antennas of more than half ofa wavelength are proposed.

Hereinafter, a method of estimating AoA and AoD based on oversampling inthe spatial domain is proposed.

FIG. 38 is an example of a basic block diagram for explaining adelta-sigma structure in the spatial domain. Here, the delta-sigmastructure may refer to a structure in which an error is obtained bypredicting or estimating a signal value and then correcting the errorusing the accumulated error.

Referring to FIG. 38 , if the Y_(Q+1) signal is looped back to Y_(Q) andthe W_(Q+1) signal is looped back to WQ, it can be referred to as adelta-sigma structure in the existing time domain. This can be expressedin the following way.

Y(z)=W(z)+(1-z⁻¹)N(z)

That is, the actual quantized signal Y is composed of the sum oforiginal signals W and N, that is, quantization errors. Here, 1-z-1 hasa difference value of quantization error in the time domain, this partcauses noise shaping, that is, a shaping effect of moving thequantization error of the low frequency part to the high frequency part.

FIG. 39 shows an example of shaping according to the basic blockdiagram.

Referring to FIG. 39 , when shaping is performed, the shape of a powerspectrum density (PSD) of a quantization error is changed. In otherwords, if noise shaping is performed on the quantization error, thetotal power of the quantization error cannot be reduced, but it can beshifted in frequency. Using this, only the bandwidth of the desiredsignal is extracted through a filter, and thus the quality of the ADCoutput signal can be improved. Meanwhile, fs in FIG. 39 may mean asampling frequency.

Based on the foregoing, a spatial domain noise shaping method in atwo-dimensional antenna structure is proposed below.

(Option 1) A Structure that Simultaneously Estimates Horizontal andVertical AoAs Using a Divider

Option 1 proposes a structure that simultaneously performs noise shapingin a horizontal domain and a vertical domain. To this end, a structurein which a received signal from an antenna is divided into a path forperforming horizontal domain noise shaping and a path for performingvertical domain noise shaping through a divider after passing through anRF chain may be considered.

FIG. 40 shows an example of an AoA estimation structure based on Option1.

Referring to FIG. 40 , it is divided into a path for performinghorizontal domain noise shaping and a path for performing verticaldomain noise shaping. Here, W(index1, index2) denotes a received analogsignal that has passed through the RF chain from the antennas of index 1in the horizontal direction and index2 in the vertical direction. Inaddition, Y(index1, index2) denotes a digital signal transmitted to thefinal baseband through the ADC after passing through the RF chain fromthe antenna of index 1 in the horizontal direction and index2 in thevertical direction.

Referring to the horizontal domain noise shaping part, basically, theoutput and input of the above-mentioned single blocks are continuouslyconnected. That is, outputs and inputs are connected in the horizontaldirection for AoA in the horizontal direction, whereas outputs andinputs of single blocks are connected in the vertical direction forvertical domain noise shaping. When passing through the 1-bit ADCthrough the above structure, AoA and AoD can be more accuratelyestimated.

(Option 2) Optional AoA Estimation Structure in Vertical and HorizontalDomains Using Switches

In the case of option 1, AoA is simultaneously estimated in thehorizontal and vertical directions, whereas option 2 proposes astructure in which AoA is selectively estimated in the vertical orhorizontal direction through a switch.

FIG. 41 shows an example of an AoA estimation structure based on Option2.

Referring to FIG. 41 , AoA may be selectively estimated through a switchrather than a divider. In Option 2, power is divided in half in the caseof the divider, while the switch selectively selects the horizontal orvertical direction, allowing more precise estimation of the AoA in aspecific direction without reducing power.

Hereinafter, a method for enhancing AoA and AoD estimation based oncontinuous transmission of signals is proposed. Specifically, below, aphase resolution enhancement method using a transmission rotated signalfor AoA and AoD estimation in a system including a 1-bit ADC receiver isproposed.

Meanwhile, although the above method is described based on Nyquistsampling, it is obvious that the same can be applied to oversampling andundersampling.

During transmission, by transmitting a known signal, for example, acontinuous reference signal, the receiving end can increase phaseresolution through the received signal.

As an example, a method of increasing the phase resolution by 2 times bycontinuously transmitting the reference signal twice will be described.

FIG. 42 schematically illustrates an example of a method for increasingphase resolution.

Referring to FIG. 42 , the transmitter rotates the phase of thereference signal by π/4 and transmits it twice, the receiving end candetect the received signal of the reference signal and estimate thephase with a resolution of π/4 from the existing π/2 resolution. Byutilizing this, AoA estimation performance can be enhanced.

Next, an example in which the phase of the reference signal is rotatedby π/8 and transmitted four times will be described.

FIG. 43 schematically illustrates another example of a method forincreasing phase resolution.

Referring to FIG. 43 , the receiving end can estimate the phase from theexisting π/2 resolution to π/8 resolution by looking at the receivedsignals for the four reference signals.

Therefore, by rotating the phase by π/(2^(M+1)) in the transmitter andtransmitting it N times, the receiver can have a resolution ofπ/(2^(M+1)). Through this, AoA can be measured more precisely. Here, itmay be N=2^(M+1).

Alternatively, the receiver may have a resolution of π/(2N) by rotatingthe phase by π/(2N) in the transmitter and transmitting N times.

The receiver may signal the type of reference signal to the transmitteraccording to the AoA or AoD resolution condition. For example, when aresolution of π/8 is required, the transmitter and receiver can make anappointment by signaling RS type=2. That is, a resolution value set foreach type of reference signal may be defined in advance, a referencesignal related to a specific resolution value may be transmitted throughsignaling between a transmitter and a receiver.

On the other hand, although the above-described method described thegranularity of the resolution as a multiple of 2, it is obvious that itis applicable even when the resolution is not a multiple of 2. Inaddition, although the above method has been described in terms of AoA,it is obvious that it is applicable to AoD.

FIG. 44 is a flowchart of an example of a method for measuring an angleof a received signal of a first communication device according to someimplementations of the present disclosure.

Referring to FIG. 44 , the first communication device receives signalstransmitted n times by the second communication device through a 1-bitanalog-to-digital converter (ADC) (S4410). Here, n may be an integer of2 or greater.

Thereafter, the first communication device estimates the angle of thesignal (S4420).

Here, the phase difference of each signal transmitted over the n timesmay have a specific value.

Meanwhile, the first communication device and each of the firstcommunication devices may be a terminal or a base station.

The claims described in the present disclosure may be combined invarious manners. For example, the technical features of the methodclaims of the present disclosure may be combined and implemented as anapparatus, and the technical features of the apparatus claims of thepresent disclosure may be combined and implemented as a method. Inaddition, the technical features of the method claims of the presentdisclosure and the technical features of the apparatus claims may becombined and implemented as an apparatus, and the technical features ofthe method claims of the present disclosure and the technical featuresof the apparatus claims may be combined and implemented as a method.

In addition to a UE, the methods proposed in the present disclosure maybe performed by an apparatus configured to control the UE, whichincludes at least one computer-readable recording medium including aninstruction based on being executed by at least one processor, one ormore processors, and one or more memories operably coupled by the one ormore processors and storing instructions, wherein the one or moreprocessors execute the instructions to perform the methods proposed inthe present disclosure. Further, it is obvious that an operation of abase station corresponding to an operation performed by the UE may beconsidered according to the methods proposed in the present disclosure.

Hereinafter, an example of a communication system to which thedisclosure is applied is described.

Various descriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed herein may be applied to, but notlimited to, various fields requiring wireless communication/connection(e.g., 5G) between devices.

Hereinafter, specific examples are illustrated with reference todrawings. In the following drawings/description, unless otherwiseindicated, like reference numerals may refer to like or correspondinghardware blocks, software blocks, or functional blocks.

FIG. 45 illustrates a communication system 1 applied to the disclosure.

Referring to FIG. 45 , the communication system 1 applied to thedisclosure includes a wireless device, a base station, and a network.Here, the wireless device refers to a device that performs communicationusing a radio access technology (e.g., 5G new RAT (NR) or Long-TermEvolution (LTE)) and may be referred to as a communication/wireless/5Gdevice. The wireless device may include, but limited to, a robot 100 a,a vehicle 100 b-1 and 100 b-2, an extended reality (XR) device 100 c, ahand-held device 100 d, a home appliance 100 e, an Internet of things(IoT) device 100 f, and an AI device/server 400. For example, thevehicle may include a vehicle having a wireless communication function,an autonomous driving vehicle, a vehicle capable of inter-vehiclecommunication, or the like. Here, the vehicle may include an unmannedaerial vehicle (UAV) (e.g., a drone). The XR device may includeaugmented reality (AR)/virtual reality (VR)/mixed reality (MR) devicesand may be configured as a head-mounted device (HMD), a vehicularhead-up display (HUD), a television, a smartphone, a computer, awearable device, a home appliance, digital signage, a vehicle, a robot,or the like. The hand-held device may include a smartphone, a smartpad,a wearable device (e.g., a smart watch or smart glasses), and a computer(e.g., a notebook). The home appliance may include a TV, a refrigerator,a washing machine, and the like. The IoT device may include a sensor, asmart meter, and the like. The base station and the network may beconfigured, for example, as wireless devices, and a specific wirelessdevice 200 a may operate as a base station/network node for otherwireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300through the base station 200. Artificial intelligence (AI) technologymay be applied to the wireless devices 100 a to 100 f, and the wirelessdevices 100 a to 100 f may be connected to an AI server 400 through thenetwork 300. The network 300 may be configured using a 3G network, a 4G(e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices100 a to 100 f may communicate with each other via the base station200/network 300 and may also perform direct communication (e.g. sidelinkcommunication) with each other without passing through the basestation/network. For example, the vehicles 100 b-1 and 100 b-2 mayperform direct communication (e.g. vehicle-to-vehicle(V2V)/vehicle-to-everything (V2X) communication). Further, the IoTdevice (e.g., a sensor) may directly communicate with another IoT device(e.g., a sensor) or another wireless device 100 a to 100 f.

Wireless communications/connections 150 a, 150 b, and 150 c may beestablished between the wireless devices 100 a to 100 f and the basestation 200 and between the base stations 200. Here, the wirelesscommunications/connections may be established by various wireless accesstechnologies (e.g., 5G NR), such as uplink/downlink communication 150 a,sidelink communication 150 b (or D2D communication), and inter-basestation communication 150 c (e.g., relay or integrated access backhaul(IAB)). The wireless devices and the base station/wireless devices, andthe base stations may transmit/receive radio signals to/from each otherthrough the wireless communications/connections 150 a, 150 b, and 150 c.For example, the wireless communications/connections 150 a, 150 b, and150 c may transmit/receive signals over various physical channels. Tothis end, at least some of various configuration information settingprocesses, various signal processing processes (e.g., channelencoding/decoding, modulation/demodulation, resource mapping/demapping,and the like), and resource allocation processes may be performed on thebasis of various proposals of the disclosure.

FIG. 46 illustrates a wireless device that is applicable to thedisclosure.

Referring to FIG. 46 , a first wireless device 100 and a second wirelessdevice 200 may transmit and receive radio signals through various radioaccess technologies (e.g., LTE and NR). Here, the first wireless device100 and the second wireless device 200 may respectively correspond to awireless device 100 x and the base station 200 of FIG. 45 and/or mayrespectively correspond to a wireless device 100 x and a wireless device100 x of FIG. 45 .

The first wireless device 100 includes at least one processor 102 and atleast one memory 104 and may further include at least one transceiver106 and/or at least one antenna 108. The processor 102 may be configuredto control the memory 104 and/or the transceiver 106 and to implementthe descriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed herein. For example, the processor 102may process information in the memory 104 to generate firstinformation/signal and may then transmit a radio signal including thefirst information/signal through the transceiver 106. In addition, theprocessor 102 may receive a radio signal including secondinformation/signal through the transceiver 106 and may store informationobtained from signal processing of the second information/signal in thememory 104. The memory 104 may be connected to the processor 102 and maystore various pieces of information related to the operation of theprocessor 102. For example, the memory 104 may store a software codeincluding instructions to perform some or all of processes controlled bythe processor 102 or to perform the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed herein.Here, the processor 102 and the memory 104 may be part of acommunication modem/circuit/chip designed to implement a radiocommunication technology (e.g., LTE or NR). The transceiver 106 may beconnected with the processor 102 and may transmit and/or receive a radiosignal via the at least one antennas 108. The transceiver 106 mayinclude a transmitter and/or a receiver. The transceiver 106 may bereplaced with a radio frequency (RF) unit. In the disclosure, thewireless device may refer to a communication modem/circuit/chip.

The second wireless device 200 includes at least one processor 202 andat least one memory 204 and may further include at least one transceiver206 and/or at least one antenna 208. The processor 202 may be configuredto control the memory 204 and/or the transceiver 206 and to implementthe descriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed herein. For example, the processor 202may process information in the memory 204 to generate thirdinformation/signal and may then transmit a radio signal including thethird information/signal through the transceiver 206. In addition, theprocessor 202 may receive a radio signal including fourthinformation/signal through the transceiver 206 and may store informationobtained from signal processing of the fourth information/signal in thememory 204. The memory 204 may be connected to the processor 202 and maystore various pieces of information related to the operation of theprocessor 202. For example, the memory 204 may store a software codeincluding instructions to perform some or all of processes controlled bythe processor 202 or to perform the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed herein.Here, the processor 202 and the memory 204 may be part of acommunication modem/circuit/chip designed to implement a radiocommunication technology (e.g., LTE or NR). The transceiver 206 may beconnected with the processor 202 and may transmit and/or receive a radiosignal via the at least one antennas 208. The transceiver 206 mayinclude a transmitter and/or a receiver. The transceiver 206 may bereplaced with an RF unit. In the disclosure, the wireless device mayrefer to a communication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 aredescribed in detail. At least one protocol layer may be implemented, butlimited to, by the at least one processor 102 and 202. For example, theat least one processor 102 and 202 may implement at least one layer(e.g., a functional layer, such as PHY, MAC, RLC, PDCP, RRC, and SDAPlayers). The at least one processor 102 and 202 may generate at leastone protocol data unit (PDU) and/or at least one service data unit (SDU)according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed herein. The at leastone processor 102 and 202 may generate a message, control information,data, or information according to the descriptions, functions,procedures, proposals, methods, and/or operational flowcharts disclosedherein. The at least one processor 102 and 202 may generate a signal(e.g., a baseband signal) including a PDU, an SDU, a message, controlinformation, data, or information according to the functions,procedures, proposals, and/or methods disclosed herein and may providethe signal to the at least one transceiver 106 and 206. The at least oneprocessor 102 and 202 may receive a signal (e.g., a baseband signal)from the at least one transceiver 106 and 206 and may obtain a PDU, anSDU, a message, control information, data, or information according tothe descriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed herein.

The at least one processor 102 and 202 may be referred to as acontroller, a microcontroller, a microprocessor, or a microcomputer. Theat least one processor 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. For example, at least oneapplication-specific integrated circuit (ASIC), at least one digitalsignal processor (DSP), at least one digital signal processing devices(DSPD), at least one programmable logic devices (PLD), or at least onefield programmable gate array (FPGA) may be included in the at least oneprocessor 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed herein maybe implemented using firmware or software, and the firmware or softwaremay be configured to include modules, procedures, functions, and thelike. The firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed herein may be included in the at least one processor 102 and202 or may be stored in the at least one memory 104 and 204 and may beexecuted by the at least one processor 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed herein may be implemented in the form of a code, aninstruction, and/or a set of instructions using firmware or software.

The at least one memory 104 and 204 may be connected to the at least oneprocessor 102 and 202 and may store various forms of data, signals,messages, information, programs, codes, indications, and/or commands.The at least one memory 104 and 204 may be configured as a ROM, a RAM,an EPROM, a flash memory, a hard drive, a register, a cache memory, acomputer-readable storage medium, and/or a combinations thereof. The atleast one memory 104 and 204 may be disposed inside and/or outside theat least one processor 102 and 202. In addition, the at least one memory104 and 204 may be connected to the at least one processor 102 and 202through various techniques, such as a wired or wireless connection.

The at least one transceiver 106 and 206 may transmit user data, controlinformation, a radio signal/channel, or the like mentioned in themethods and/or operational flowcharts disclosed herein to at leastdifferent device. The at least one transceiver 106 and 206 may receiveuser data, control information, a radio signal/channel, or the likementioned in the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed herein from at leastone different device. For example, the at least one transceiver 106 and206 may be connected to the at least one processor 102 and 202 and maytransmit and receive a radio signal. For example, the at least oneprocessor 102 and 202 may control the at least one transceiver 106 and206 to transmit user data, control information, or a radio signal to atleast one different device. In addition, the at least one processor 102and 202 may control the at least one transceiver 106 and 206 to receiveuser data, control information, or a radio signal from at least onedifferent device. The at least one transceiver 106 and 206 may beconnected to the at least one antenna 108 and 208 and may be configuredto transmit or receive user data, control information, a radiosignal/channel, or the like mentioned in the descriptions, functions,procedures, proposals, methods, and/or operational flowcharts disclosedherein through the at least one antenna 108 and 208. In this document,the at least one antenna may be a plurality of physical antennas or maybe a plurality of logical antennas (e.g., antenna ports). The at leastone transceiver 106 and 206 may convert a received radio signal/channelfrom an RF band signal into a baseband signal in order to processreceived user data, control information, a radio signal/channel, or thelike using the at least one processor 102 and 202. The at least onetransceiver 106 and 206 may convert user data, control information, aradio signal/channel, or the like, processed using the at least oneprocessor 102 and 202, from a baseband signal to an RF bad signal. Tothis end, the at least one transceiver 106 and 206 may include an(analog) oscillator and/or a filter.

FIG. 47 illustrates a signal processing circuit for a transmissionsignal.

Referring to FIG. 47 , the signal processing circuit 1000 may include ascrambler 1010, a modulator 1020, a layer mapper 1030, a precoder 1040,a resource mapper 1050, and a signal generator 1060.Operations/functions illustrated with reference to FIG. 47 may beperformed, but not limited to, in the processor 102 and 202 and/or thetransceiver 106 and 206 of FIG. 46 . Hardware elements illustrated inFIG. 47 may be configured in the processor 102 and 202 and/or thetransceiver 106 and 206 of FIG. 46 . For example, blocks 1010 to 1060may be configured in the processor 102 and 202 of FIG. 46 .Alternatively, blocks 1010 to 1050 may be configured in the processor102 and 202 of FIG. 46 , and a block 1060 may be configured in thetransceiver 106 and 206 of FIG. 46 .

A codeword may be converted into a radio signal via the signalprocessing circuit 1000 of FIG. 47 . Here, the codeword is an encodedbit sequence of an information block. The information block may includea transport block (e.g., a UL-SCH transport block and a DL-SCH transportblock). The radio signal may be transmitted through various physicalchannels (e.g., a PUSCH or a PDSCH).

Specifically, the codeword may be converted into a scrambled bitsequence by the scrambler 1010. A scrambled sequence used for scramblingis generated on the basis of an initialization value, and theinitialization value may include ID information about a wireless device.The scrambled bit sequence may be modulated into a modulation symbolsequence by the modulator 1020. A modulation scheme may includepi/2-binary phase shift keying (pi/2-BPSK), m-phase shift keying(m-PSK), m-quadrature amplitude modulation (m-QAM), and the like. Acomplex modulation symbol sequence may be mapped to at least onetransport layer by the layer mapper 1030. Modulation symbols of eachtransport layer may be mapped to a corresponding antenna port(s) by theprecoder 1040 (precoding). Output z from the precoder 1040 may beobtained by multiplying output y from the layer mapper 1030 by aprecoding matrix W of N * M, where N is the number of antenna ports, andM is the number of transport layers. Here, the precoder 1040 may performprecoding after performing transform precoding (e.g., DFT transform) oncomplex modulation symbols. Alternatively, the precoder 1040 may performprecoding without performing transform precoding.

The resource mapper 1050 may map a modulation symbol of each antennaport to a time-frequency resource. The time-frequency resource mayinclude a plurality of symbols (e.g., CP-OFDMA symbols or DFT-s-OFDMAsymbols) in the time domain and may include a plurality of subcarriersin the frequency domain. The signal generator 1060 may generate a radiosignal from mapped modulation symbols, and the generated radio signalmay be transmitted to another device through each antenna. To this end,the signal generator 1060 may include an inverse fast Fourier transform(IFFT) module, a cyclic prefix (CP) inserter, a digital-to-analogconverter (DAC), a frequency upconverter, and the like.

A signal processing procedure for a received signal in a wireless devicemay be performed in the reverse order of the signal processing procedure1010 to 1060 of FIG. 47 . For example, a wireless device (e.g., 100 and200 of FIG. 46 ) may receive a radio signal from the outside through anantenna port/transceiver. The received radio signal may be convertedinto a baseband signal through a signal reconstructor. To this end, thesignal reconstructor may include a frequency downconverter, ananalog-to-digital converter (ADC), a CP remover, and a fast Fouriertransform (FFT) module. The baseband signal may be reconstructed to acodeword through resource demapping, postcoding, demodulation, anddescrambling. The codeword may be reconstructed to an originalinformation block through decoding. Thus, a signal processing circuit(not shown) for a received signal may include a signal reconstructor, aresource demapper, a postcoder, a demodulator, a descrambler and adecoder.

FIG. 48 illustrates another example of a wireless device applied to thedisclosure. The wireless device may be configured in various formsdepending on usage/service.

Referring to FIG. 48 , the wireless devices 100 and 200 may correspondto the wireless device 100 and 200 of FIG. 46 and may include variouselements, components, units, and/or modules. For example, the wirelessdevice 100 and 200 may include a communication unit 110, a control unit120, a memory unit 130, and additional components 140. The communicationunit may include a communication circuit 112 and a transceiver(s) 114.For example, the communication circuit 112 may include the at least oneprocessor 102 and 202 and/or the at least one memory 104 and 204 of FIG.46 . For example, the transceiver(s) 114 may include the at least onetransceiver 106 and 206 and/or the at least one antenna 108 and 208 ofFIG. 46 . The control unit 120 is electrically connected to thecommunication unit 110, the memory unit 130, and the additionalcomponents 140 and controls overall operations of the wireless device.For example, the control unit 120 may control electrical/mechanicaloperations of the wireless device on the basis of aprogram/code/command/information stored in the memory unit 130. Inaddition, the control unit 120 may transmit information stored in thememory unit 130 to the outside (e.g., a different communication device)through a wireless/wired interface via the communication unit 110 or maystore, in the memory unit 130, information received from the outside(e.g., a different communication device) through the wireless/wiredinterface via the communication unit 110.

The additional components 140 may be configured variously depending onthe type of the wireless device. For example, the additional components140 may include at least one of a power unit/battery, an input/output(I/O) unit, a driving unit, and a computing unit. The wireless devicemay be configured, but not limited to, as a robot (100 a in FIG. 45 ), avehicle (100 b-1 or 100 b-2 in FIG. 45 ), an XR device (100 c in FIG. 45), a hand-held device (100 d in FIG. 45 ), a home appliance (100 e inFIG. 45 ), an IoT device (100 f in FIG. 45 ), a terminal for digitalbroadcasting, a hologram device, a public safety device, an MTC device,a medical device, a fintech device (or financial device), a securitydevice, a climate/environmental device, an AI server/device (400 in FIG.45 ), a base station (200 in FIG. 45 ), a network node, or the like. Thewireless device may be mobile or may be used in a fixed place dependingon usage/service.

In FIG. 48 , all of the various elements, components, units, and/ormodules in the wireless devices 100 and 200 may be connected to eachother through a wired interface, or at least some thereof may bewirelessly connected through the communication unit 110. For example,the control unit 120 and the communication unit 110 may be connected viaa cable in the wireless device 100 and 200, and the control unit 120 anda first unit (e.g., 130 and 140) may be wirelessly connected through thecommunication unit 110. In addition, each element, component, unit,and/or module in wireless device 100 and 200 may further include atleast one element. For example, the control unit 120 may include atleast one processor set. For example, the control unit 120 may beconfigured as a set of a communication control processor, an applicationprocessor, an electronic control unit (ECU), a graphics processingprocessor, a memory control processor, and the like. In another example,the memory unit 130 may include a random-access memory (RAM), a dynamicRAM (DRAM), a read-only memory (ROM), a flash memory, a volatile memory,a non-volatile memory, and/or a combination thereof.

Next, an illustrative configuration of FIG. 48 is described in detailwith reference to the accompanying drawing.

FIG. 49 illustrates a hand-held device applied to the disclosure. Thehand-held device may include a smartphone, a smartpad, a wearable device(e.g., a smart watch or smart glasses), and a portable computer (e.g., anotebook). The hand-held device may be referred to as a mobile station(MS), a user terminal (UT), a mobile subscriber station (MSS), asubscriber station (SS), an advanced mobile station (AMS), or a wirelessterminal (WT).

Referring to FIG. 49 , the hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and aninput/output unit 140 c. The antenna unit 108 may be configured as apart of the communication unit 110. Blocks 110 to 130/140 a to 140 ccorrespond to the blocks 110 to 130/140 in FIG. 48 , respectively.

The communication unit 110 may transmit and receive a signal (e.g.,data, a control signal, or the like) to and from other wireless devicesand base stations. The control unit 120 may control various componentsof the hand-held device 100 to perform various operations. The controlunit 120 may include an application processor (AP). The memory unit 130may store data/parameter/program/code/command necessary to drive thehand-held device 100. Further, the memory unit 130 may storeinput/output data/information. The power supply unit 140 a suppliespower to the hand-held device 100 and may include a wired/wirelesscharging circuit, a battery, and the like. The interface unit 140 b maysupport a connection between the hand-held device 100 and a differentexternal device. The interface unit 140 b may include various ports(e.g., an audio input/output port and a video input/output port) forconnection to an external device. The input/output unit 140 c mayreceive or output image information/signal, audio information/signal,data, and/or information input from a user. The input/output unit 140 cmay include a camera, a microphone, a user input unit, a display unit140 d, a speaker, and/or a haptic module.

For example, in data communication, the input/output unit 140 c mayobtain information/signal (e.g., a touch, text, voice, an image, and avideo) input from the user, and the obtained information/signal may bestored in the memory unit 130. The communication unit 110 may convertinformation/signal stored in the memory unit into a radio signal and maytransmit the converted radio signal directly to a different wirelessdevice or to a base station. In addition, the communication unit 110 mayreceive a radio signal from a different wireless device or the basestation and may reconstruct the received radio signal to originalinformation/signal. The reconstructed information/signal may be storedin the memory unit 130 and may then be output in various forms (e.g.,text, voice, an image, a video, and a haptic form) through theinput/output unit 140 c.

FIG. 50 illustrates a vehicle or an autonomous driving vehicle appliedto the disclosure. The vehicle or the autonomous driving may beconfigured as a mobile robot, a car, a train, a manned/unmanned aerialvehicle (AV), a ship, or the like.

Referring to FIG. 50 , the vehicle or the autonomous driving vehicle 100may include an antenna unit 108, a communication unit 110, a controlunit 120, a driving unit 140 a, a power supply unit 140 b, a sensor unit140 c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110. Blocks 110/130/140 ato 140 d correspond to the blocks 110/130/140 in FIG. 48 , respectively.

The communication unit 110 may transmit and receive a signal (e.g.,data, a control signal, or the like) to and from external devices, suchas a different vehicle, a base station (e.g. a base station, a road-sideunit, or the like), and a server. The control unit 120 may controlelements of the vehicle or the autonomous driving vehicle 100 to performvarious operations. The control unit 120 may include an electroniccontrol unit (ECU). The driving unit 140 a may enable the vehicle or theautonomous driving vehicle 100 to run on the ground. The driving unit140 a may include an engine, a motor, a power train, wheels, a brake, asteering device, and the like. The power supply unit 140 b suppliespower to the vehicle or the autonomous driving vehicle 100 and mayinclude a wired/wireless charging circuit, a battery, and the like. Thesensor unit 140 c may obtain a vehicle condition, environmentalinformation, user information, and the like. The sensor unit 140 c mayinclude an inertial measurement unit (IMU) sensor, a collision sensor, awheel sensor, a speed sensor, an inclination sensor, a weight sensor, aheading sensor, a position module, vehiclular forward/backward visionsensors, a battery sensor, a fuel sensor, a tire sensor, a steeringsensor, a temperature sensor, a humidity sensor, an ultrasonic sensor,an illuminance sensor, a pedal position sensor, and the like. Theautonomous driving unit 140 d may implement a technology for maintaininga driving lane, a technology for automatically adjusting speed, such asadaptive cruise control, a technology for automatic driving along a setroute, a technology for automatically setting a route and driving when adestination is set, and the like.

For example, the communication unit 110 may receive map data, trafficcondition data, and the like from an external server. The autonomousdriving unit 140 d may generate an autonomous driving route and adriving plan on the basis of obtained data. The control unit 120 maycontrol the driving unit 140 a to move the vehicle or the autonomousdriving vehicle 100 along the autonomous driving route according to thedriving plan (e.g., speed/direction control). During autonomous driving,the communication unit 110 may aperiodically/periodically obtain updatedtraffic condition data from the external server and may obtainsurrounding traffic condition data from a neighboring vehicle. Further,during autonomous driving, the sensor unit 140 c may obtain a vehiclecondition and environmental information. The autonomous driving unit 140d may update the autonomous driving route and the driving plan on thebasis of newly obtained data/information. The communication unit 110 maytransmit information about a vehicle location, an autonomous drivingroute, a driving plan, and the like to the external server. The externalserver may predict traffic condition data in advance using AI technologyor the like on the basis of information collected from vehicles orautonomous driving vehicles and may provide the predicted trafficcondition data to the vehicles or the autonomous driving vehicles.

FIG. 51 illustrates a vehicle applied to the disclosure. The vehicle maybe implemented as a means of transportation, a train, an air vehicle, aship, and the like.

Referring to FIG. 51 , the vehicle 100 may include a communication unit110, a control unit 120, a memory unit 130, an input/output unit 140 a,and a positioning unit 140 b. Herein, blocks 110 to 130/140 a to 140 bcorrespond to block 110 to 130/140 of FIG. 48 , respectively.

The communication unit 110 may transmit/receive signals (e.g., data,control signals, etc.) with other vehicles or external devices such as abase station. The control unit 120 may control components of the vehicle100 to perform various operations. The memory unit 130 may storedata/parameters/programs/codes/commands supporting various functions ofthe vehicle 100. The input/output unit 140 a may output an AR/VR objectbased on information in the memory unit 130. The input/output unit 140 amay include a HUD. The positioning unit 140 b may acquire positioninformation of the vehicle 100. The location information may includeabsolute location information of the vehicle 100, location informationwithin a driving line, acceleration information, location informationwith a neighboring vehicle, and the like. The positioning unit 140 b mayinclude a GPS and various sensors.

For example, the communication unit 110 of the vehicle 100 may receivemap information, traffic information, and the like from an externalserver and store it in the memory unit 130. The positioning unit 140 bmay obtain vehicle position information through GPS and various sensorsand store it in the memory unit 130. The control unit 120 may generate avirtual obj ect based on map information, traffic information, vehiclelocation information, and the like, and the input/output unit 140 a maydisplay the generated virtual object on a window inside the vehicle(1410 and 1420). In addition, the control unit 120 may determine whetherthe vehicle 100 is normally operating within the driving line based onthe vehicle location information. When the vehicle 100 abnormallydeviates from the driving line, the control unit 120 may display awarning on the windshield of the vehicle through the input/output unit140 a. Also, the control unit 120 may broadcast a warning messageregarding the driving abnormality to surrounding vehicles through thecommunication unit 110. Depending on the situation, the control unit 120may transmit the location information of the vehicle and information ondriving/vehicle abnormality to the related organization through thecommunication unit 110.

FIG. 52 illustrates a XR device applied to the disclosure. The XR devicemay be implemented as an HMD, a head-up display (HUD) provided in avehicle, a television, a smartphone, a computer, a wearable device, ahome appliance, a digital signage, a vehicle, a robot, and the like.

Referring to FIG. 52 , the XR device 100 a may include a communicationunit 110, a control unit 120, a memory unit 130, an input/output unit140 a, a sensor unit 140 b and a power supply unit 140 c. Herein, blocks110 to 130/140 a to 140 c correspond to blocks 110 to 130/140 in FIG. 48.

The communication unit 110 may transmit/receive signals (e.g., mediadata, control signals, etc.) to/from external devices such as otherwireless devices, portable devices, or media servers. Media data mayinclude images, images, sounds, and the like. The control unit 120 maycontrol the components of the XR device 100 a to perform variousoperations. For example, the control unit 120 may be configured tocontrol and/or perform procedures such as video/image acquisition,(video/image) encoding, and metadata generation and processing. Thememory unit 130 may store data/parameters/programs/codes/commandsnecessary for driving the XR device 100 a/creating an XR object. Theinput/output unit 140 a may obtain control information, data, and thelike from the outside, and may output the generated XR object. Theinput/output unit 140 a may include a camera, a microphone, a user inputunit, a display unit, a speaker, and/or a haptic module. The sensor unit140 b may obtain an XR device state, surrounding environmentinformation, user information, and the like. The sensor unit 140 b mayinclude a proximity sensor, an illumination sensor, an accelerationsensor, a magnetic sensor, a gyro sensor, an inertial sensor, a RGBsensor, an IR sensor, a fingerprint recognition sensor, an ultrasonicsensor, an optical sensor, a microphone, and/or a radar. The powersupply unit 140 c supplies power to the XR device 100 a, and may includea wired/wireless charging circuit, a battery, and the like.

For example, the memory unit 130 of the XR device 100 a may includeinformation (e.g., data, etc.) necessary for generating an XR object(e.g., AR/VR/MR object). The input/output unit 140 a may obtain acommand to operate the XR device 100 a from the user, and the controlunit 120 may drive the XR device 100 a according to the user’s drivingcommand. For example, when the user wants to watch a movie or newsthrough the XR device 100 a, the control unit 120 transmits the contentrequest information through the communication unit 130 to another device(e.g., the mobile device 100 b) or can be sent to the media server. Thecommunication unit 130 may download/stream contents such as movies andnews from another device (e.g., the portable device 100 b) or a mediaserver to the memory unit 130. The control unit 120 controls and/orperforms procedures such as video/image acquisition, (video/image)encoding, and metadata generation/processing for the content, and isacquired through the input/output unit 140a/the sensor unit 140 b An XRobject can be generated/output based on information about onesurrounding space or a real object.

Also, the XR device 100 a is wirelessly connected to the portable device100 b through the communication unit 110, and the operation of the XRdevice 100 a may be controlled by the portable device 100 b. Forexample, the portable device 100 b may operate as a controller for theXR device 100 a. To this end, the XR device 100 a may obtain 3D locationinformation of the portable device 100 b, and then generate and outputan XR object corresponding to the portable device 100 b.

FIG. 53 illustrates a robot applied to the disclosure. The robot may beclassified into industrial, medical, home, military, and the likedepending on the purpose or field of use.

Referring to FIG. 53 , the robot 100 may include a communication unit110, a control unit 120, a memory unit 130, an input/output unit 140 a,a sensor unit 140 b, and a driving unit 140 c. Herein, blocks 110 to130/140 a to 140 c correspond to blocks 110 to 130/140 in FIG. 48 .

The communication unit 110 may transmit/receive signals (e.g., drivinginformation, control signal, etc.) to/from external device such as otherwireless device, other robot, or a control server. The control unit 120may perform various operations by controlling the components of therobot 100. The memory unit 130 may storedata/parameters/programs/codes/commands supporting various functions ofthe robot 100. The input/output unit 140 a may obtain information fromthe outside of the robot 100 and may output information to the outsideof the robot 100. The input/output unit 140 a may include a camera, amicrophone, an user input unit, a display unit, a speaker, and/or ahaptic module, etc. The sensor unit 140 b may obtain internalinformation, surrounding environment information, user information andthe like of the robot 100. The sensor unit may include a proximitysensor, an illumination sensor, an acceleration sensor, a magneticsensor, a gyro sensor, an inertial sensor, an IR sensor, a fingerprintrecognition sensor, an ultrasonic sensor, an optical sensor, amicrophone, a radar, and the like. The driving unit 140 c may performvarious physical operations such as moving a robot joint. In addition,the driving unit 140 c may make the robot 100 travel on the ground orfly in the air. The driving unit 140 c may include an actuator, a motor,a wheel, a brake, a propeller, and the like.

FIG. 54 illustrates an AI device applied to the disclosure. The AIdevice may be implemented as a stationary device or a mobile device,such as a TV, a projector, a smartphone, a PC, a laptop, a digitalbroadcasting terminal, a tablet PC, a wearable device, a set-top box, aradio, a washing machine, a refrigerator, digital signage, a robot, anda vehicle.

Referring to FIG. 54 , the AI device 100 may include a communicationunit 110, a control unit 120, a memory unit 130, an input unit 140 a, anoutput unit 140 b, a learning processor unit 140 c, and a sensor unit140 d. Blocks 110 to 130/140 a to 140 d correspond to the blocks 110 to130/140 of FIG. 48 , respectively.

The communication unit 110 may transmit and receive wired or wirelesssignals (e.g., sensor information, a user input, a learning mode, acontrol signal, or the like) to and from external devices, a differentAI device (e.g., 100 x, 200, or 400 in FIG. 45 ) or an AI server (e.g.,400 in FIG. 45 ) using wired or wireless communication technologies. Tothis end, the communication unit 110 may transmit information in thememory unit 130 to an external device or may transmit a signal receivedfrom the external device to the memory unit 130.

The control unit 120 may determine at least one executable operation ofthe AI device 100 on the basis of information determined or generatedusing a data analysis algorithm or a machine-learning algorithm. Thecontrol unit 120 may control components of the AI device 100 to performthe determined operation. For example, the control unit 120 may request,retrieve, receive, or utilize data of the learning processor unit 140 cor the memory unit 130 and may control components of the AI device 100to perform a predicted operation or an operation determined to bepreferable among the at least one executable operation. The control unit120 may collect history information including details about an operationof the AI device 100 or a user’s feedback on the operation and may storethe history information in the memory unit 130 or the learning processorunit 140 c or may transmit the history information to an externaldevice, such as the AI server (400 in FIG. 45 ). The collected historyinformation may be used to update a learning model.

The memory unit 130 may store data for supporting various functions ofthe AI device 100. For example, the memory unit 130 may store dataobtained from the input unit 140 a, data obtained from the communicationunit 110, output data from the learning processor unit 140 c, and dataobtained from the sensing unit 140. Further, the memory unit 130 maystore control information and/or a software code necessary for theoperation/execution of the control unit 120.

The input unit 140 a may obtain various types of data from the outsideof the AI device 100. For example, the input unit 140 a may obtainlearning data for model learning and input data to which a learningmodel is applied. The input unit 140 a may include a camera, amicrophone, and/or a user input unit. The output unit 140 b may generatevisual, auditory, or tactile output. The output unit 140 b may include adisplay unit, a speaker, and/or a haptic module. The sensing unit 140may obtain at least one of internal information about the AI device 100,environmental information about the AI device 100, and user informationusing various sensors. The sensing unit 140 may include a proximitysensor, an illuminance sensor, an acceleration sensor, a magneticsensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor,a fingerprint sensor, an ultrasonic sensor, an optical sensor, amicrophone, and/or a radar.

The learning processor unit 140 c may train a model including artificialneural networks using learning data. The learning processor unit 140 cmay perform AI processing together with a learning processor unit of anAI server (400 in FIG. 45 ). The learning processor unit 140 c mayprocess information received from an external device through thecommunication unit 110 and/or information stored in the memory unit 130.In addition, an output value from the learning processor unit 140 c maybe transmitted to an external device through the communication unit 110and/or may be stored in the memory unit 130.

1. A method for a received signal angle estimation, the method performedby a first communication device and comprising: receiving signalstransmitted over n times by a second communication device through a1-bit analog-to-digital converter (ADC), wherein the n is an integergreater than or equal to 2, and estimating an angle of the signals,wherein a phase difference of each of the signals transmitted over the ntimes has a specific value.
 2. The method of claim 1, wherein the angleis an angle of departure or an angle of arrival.
 3. The method of claim1, wherein the n is 2^(m+1), wherein the m is an integer greater than orequal to
 0. 4. The method of claim 3, wherein the specific value is π /(2^(m+) ¹).
 5. The method of claim 1, wherein the signals are areference signal.
 6. The method of claim 5, wherein, based on the firstcommunication device signaling a type of the reference signal to thesecond communication device, the first communication device receives thereference signal.
 7. The method of claim 5, wherein a value of the n isdifferent for each type of the reference signal.
 8. The method of claim7, wherein the value of the n is predefined for the each type of thereference signal.
 9. The method of claim 1, wherein a distance betweenantennas of the first communication device is 0.5 times or more of awavelength of a transmission frequency.
 10. The method of claim 1,wherein each of the first communication device and the secondcommunication device is a terminal or a base station.
 11. A firstcommunication device comprising: at least one memory to storeinstructions; at least one transceiver; and at least one processorcoupling the at least one memory and the at least one transceiver,wherein the at least one processor execute the instructions for:receiving signals transmitted over n times by a second communicationdevice through a 1-bit analog-to-digital converter (ADC), wherein the nis an integer greater than or equal to 2, and estimating an angle of thesignals, wherein a phase difference of each of the signals transmittedover the n times has a specific value.
 12. A method for a receivedsignal angle estimation, the method performed by a first communicationdevice and comprising: receiving a signal from a second communicationdevice through a 1-bit analog-to-digital converter (ADC), and performingan angle estimation of the signal, wherein the angle estimation isperformed based on vertical arrangement estimation and horizontalarrangement estimation based on antennas arranged in two dimensions atthe first communication device.
 13. The method of claim 12, wherein thevertical arrangement estimation and the horizontal arrangementestimation are performed simultaneously based on a divider.
 14. Themethod of claim 12, wherein the vertical arrangement estimation and thehorizontal arrangement estimation are selectively performed based on aswitch.
 15. The method of claim 12, wherein the angle estimation is anestimation of angle of departure or an estimation angle of arrival.16-17. (canceled)